diff --git a/app/Config/Validation/OSPOSRules.php b/app/Config/Validation/OSPOSRules.php
index eb965ab53..49be9f367 100644
--- a/app/Config/Validation/OSPOSRules.php
+++ b/app/Config/Validation/OSPOSRules.php
@@ -135,4 +135,19 @@ class OSPOSRules
     {
         return parse_decimals($candidate) !== false;
     }
+
+    /**
+     * Validates that a locale-aware decimal value is non-negative (>= 0).
+     *
+     * @param string $candidate
+     * @param string|null $error
+     * @return bool
+     * @noinspection PhpUnused
+     */
+    public function nonNegativeDecimal(string $candidate, ?string &$error = null): bool
+    {
+        $value = parse_decimals($candidate);
+
+        return $value !== false && $value >= 0;
+    }
 }
diff --git a/app/Controllers/Sales.php b/app/Controllers/Sales.php
index c618a82e0..e90e82d07 100644
--- a/app/Controllers/Sales.php
+++ b/app/Controllers/Sales.php
@@ -582,12 +582,21 @@ class Sales extends Secure_Controller
         $data = [];
 
         $rules = [
-            'price'    => 'trim|required|decimal_locale',
+            'price'    => 'trim|required|decimal_locale|nonNegativeDecimal',
             'quantity' => 'trim|required|decimal_locale',
-            'discount' => 'trim|permit_empty|decimal_locale',
+            'discount' => 'trim|permit_empty|decimal_locale|nonNegativeDecimal',
         ];
 
-        if ($this->validate($rules)) {
+        $messages = [
+            'price' => [
+                'nonNegativeDecimal' => lang('Sales.negative_price_invalid'),
+            ],
+            'discount' => [
+                'nonNegativeDecimal' => lang('Sales.negative_discount_invalid'),
+            ],
+        ];
+
+        if ($this->validate($rules, $messages)) {
             $description = $this->request->getPost('description', FILTER_SANITIZE_FULL_SPECIAL_CHARS);
             $serialnumber = $this->request->getPost('serialnumber', FILTER_SANITIZE_FULL_SPECIAL_CHARS);
             $price = parse_decimals($this->request->getPost('price'));
@@ -596,20 +605,38 @@ class Sales extends Secure_Controller
             $discount = $discount_type
                 ? parse_quantity($this->request->getPost('discount'))
                 : parse_decimals($this->request->getPost('discount'));
+            $discount = $discount ?: 0;
+
+            // Return mode legitimately uses negative quantities for refunds
+            if ($this->sale_lib->get_mode() != 'return' && $quantity < 0) {
+                $data['error'] = lang('Sales.negative_quantity_invalid');
+                return $this->_reload($data);
+            }
+
+            // Business logic: discount bounds depend on discount_type and item values
+            if ($discount_type == PERCENT && $discount > 100) {
+                $data['error'] = lang('Sales.discount_percent_exceeds_100');
+                return $this->_reload($data);
+            }
+
+            if ($discount_type == FIXED && bccomp((string)$discount, bcmul((string)abs($quantity), (string)$price, 2), 2) > 0) {
+                $data['error'] = lang('Sales.discount_exceeds_item_total');
+                return $this->_reload($data);
+            }
 
             $item_location = $this->request->getPost('location', FILTER_SANITIZE_NUMBER_INT);
             $discounted_total = $this->request->getPost('discounted_total') != ''
                 ? parse_decimals($this->request->getPost('discounted_total') ?? '')
                 : null;
 
-
             $this->sale_lib->edit_item($line, $description, $serialnumber, $quantity, $discount, $discount_type, $price, $discounted_total);
 
             $this->sale_lib->empty_payments();
 
             $data['warning'] = $this->sale_lib->out_of_stock($this->sale_lib->get_item_id($line), $item_location);
         } else {
-            $data['error'] = lang('Sales.error_editing_item');
+            $errors = $this->validator->getErrors();
+            $data['error'] = $errors ? reset($errors) : lang('Sales.error_editing_item');
         }
 
         return $this->_reload($data);
@@ -723,6 +750,12 @@ class Sales extends Secure_Controller
         $data['cash_amount_due'] = $totals['cash_amount_due'];
         $data['non_cash_amount_due'] = $totals['amount_due'];
 
+        // Prevent negative total sales (fraud/theft vector) - returns can have negative totals for legitimate refunds
+        if ($this->sale_lib->get_mode() != 'return' && bccomp($totals['total'], '0') < 0) {
+            $data['error'] = lang('Sales.negative_total_invalid');
+            return $this->_reload($data);
+        }
+
         if ($data['cash_mode']) {    // TODO: Convert this to ternary notation
             $data['amount_due'] = $totals['cash_amount_due'];
         } else {
diff --git a/app/Language/ar-EG/Sales.php b/app/Language/ar-EG/Sales.php
index bf8d5b7cd..85dc8f9ee 100644
--- a/app/Language/ar-EG/Sales.php
+++ b/app/Language/ar-EG/Sales.php
@@ -73,6 +73,12 @@ return [
     "employee"                         => "الموظف",
     "entry"                            => "ادخال",
     "error_editing_item"               => "خطاء فى تحرير الصنف",
+    "negative_price_invalid"           => "",
+    "negative_quantity_invalid"        => "",
+    "negative_discount_invalid"        => "",
+    "discount_percent_exceeds_100"     => "",
+    "discount_exceeds_item_total"      => "",
+    "negative_total_invalid"           => "",
     "find_or_scan_item"                => "بحث/مسح باركود صنف",
     "find_or_scan_item_or_receipt"     => "بحث/مسح باركود صنف أو ايصال",
     "giftcard"                         => "بطاقة هدية",
diff --git a/app/Language/ar-LB/Sales.php b/app/Language/ar-LB/Sales.php
index 112838301..ecbe859c9 100644
--- a/app/Language/ar-LB/Sales.php
+++ b/app/Language/ar-LB/Sales.php
@@ -73,6 +73,12 @@ return [
     "employee"                         => "الموظف",
     "entry"                            => "ادخال",
     "error_editing_item"               => "خطاء فى تعديل المادة",
+    "negative_price_invalid"           => "",
+    "negative_quantity_invalid"        => "",
+    "negative_discount_invalid"        => "",
+    "discount_percent_exceeds_100"     => "",
+    "discount_exceeds_item_total"      => "",
+    "negative_total_invalid"           => "",
     "find_or_scan_item"                => "بحث/مسح باركود المادة",
     "find_or_scan_item_or_receipt"     => "بحث/مسح باركود المادة أو الايصال",
     "giftcard"                         => "بطاقة هدية",
diff --git a/app/Language/az/Sales.php b/app/Language/az/Sales.php
index 4ab9586c9..b2e47a35e 100644
--- a/app/Language/az/Sales.php
+++ b/app/Language/az/Sales.php
@@ -73,6 +73,12 @@ return [
     "employee"                         => "Əməkdaş",
     "entry"                            => "Daxil",
     "error_editing_item"               => "XƏTA Malın redaktəsində",
+    "negative_price_invalid"           => "",
+    "negative_quantity_invalid"        => "",
+    "negative_discount_invalid"        => "",
+    "discount_percent_exceeds_100"     => "",
+    "discount_exceeds_item_total"      => "",
+    "negative_total_invalid"           => "",
     "find_or_scan_item"                => "Malın axtarışı",
     "find_or_scan_item_or_receipt"     => "Tapmaq skan etmək və ya kvitansiya",
     "giftcard"                         => "Hədiyyə Kartı",
diff --git a/app/Language/bg/Sales.php b/app/Language/bg/Sales.php
index 43293ef6f..63a551553 100644
--- a/app/Language/bg/Sales.php
+++ b/app/Language/bg/Sales.php
@@ -73,6 +73,12 @@ return [
     "employee"                         => "Служител",
     "entry"                            => "Вход",
     "error_editing_item"               => "Грешка при редактирането на елемента",
+    "negative_price_invalid"           => "",
+    "negative_quantity_invalid"        => "",
+    "negative_discount_invalid"        => "",
+    "discount_percent_exceeds_100"     => "",
+    "discount_exceeds_item_total"      => "",
+    "negative_total_invalid"           => "",
     "find_or_scan_item"                => "Намерете или сканирайте елемента",
     "find_or_scan_item_or_receipt"     => "Намерете или сканирайте елемент или разпис",
     "giftcard"                         => "Gift Карта",
diff --git a/app/Language/bs/Sales.php b/app/Language/bs/Sales.php
index f623af079..ec725cba7 100644
--- a/app/Language/bs/Sales.php
+++ b/app/Language/bs/Sales.php
@@ -73,6 +73,12 @@ return [
     "employee"                         => "Zaposlenik",
     "entry"                            => "Ulaz",
     "error_editing_item"               => "Greška pri uređivanju artikla",
+    "negative_price_invalid"           => "",
+    "negative_quantity_invalid"        => "",
+    "negative_discount_invalid"        => "",
+    "discount_percent_exceeds_100"     => "",
+    "discount_exceeds_item_total"      => "",
+    "negative_total_invalid"           => "",
     "find_or_scan_item"                => "Pronađi/Skeniraj artikal",
     "find_or_scan_item_or_receipt"     => "Pronađi/Skeniraj artikal ili priznanicu",
     "giftcard"                         => "Poklon kartica",
diff --git a/app/Language/ckb/Sales.php b/app/Language/ckb/Sales.php
index 7f5d46dc2..3c7973f99 100644
--- a/app/Language/ckb/Sales.php
+++ b/app/Language/ckb/Sales.php
@@ -73,6 +73,12 @@ return [
     'employee' => "فەرمانبەر",
     'entry' => "تۆمار",
     'error_editing_item' => "هەڵە لە دەستکاریکردنی ئایتم",
+    "negative_price_invalid"           => "",
+    "negative_quantity_invalid"        => "",
+    "negative_discount_invalid"        => "",
+    "discount_percent_exceeds_100"     => "",
+    "discount_exceeds_item_total"      => "",
+    "negative_total_invalid"           => "",
     'find_or_scan_item' => "دۆزینەوە یان سکانکردنی ئایتم",
     'find_or_scan_item_or_receipt' => "دۆزینەوە یان سکانکردنی ئایتم یان پسوڵە",
     'giftcard' => "کارتی دیاری",
diff --git a/app/Language/cs/Sales.php b/app/Language/cs/Sales.php
index 623446543..999ee8474 100644
--- a/app/Language/cs/Sales.php
+++ b/app/Language/cs/Sales.php
@@ -73,6 +73,12 @@ return [
     "employee"                         => "Prodávající",
     "entry"                            => "Záznam",
     "error_editing_item"               => "Chyba při úpravě položky",
+    "negative_price_invalid"           => "",
+    "negative_quantity_invalid"        => "",
+    "negative_discount_invalid"        => "",
+    "discount_percent_exceeds_100"     => "",
+    "discount_exceeds_item_total"      => "",
+    "negative_total_invalid"           => "",
     "find_or_scan_item"                => "Najít nebo skenovat položku",
     "find_or_scan_item_or_receipt"     => "Najít nebo skenovat položku či účtenku",
     "giftcard"                         => "Dárkový poukaz",
diff --git a/app/Language/da/Sales.php b/app/Language/da/Sales.php
index ee07a62eb..ccdf0d830 100644
--- a/app/Language/da/Sales.php
+++ b/app/Language/da/Sales.php
@@ -73,6 +73,12 @@ return [
     "employee"                         => "",
     "entry"                            => "",
     "error_editing_item"               => "",
+    "negative_price_invalid"           => "",
+    "negative_quantity_invalid"        => "",
+    "negative_discount_invalid"        => "",
+    "discount_percent_exceeds_100"     => "",
+    "discount_exceeds_item_total"      => "",
+    "negative_total_invalid"           => "",
     "find_or_scan_item"                => "",
     "find_or_scan_item_or_receipt"     => "",
     "giftcard"                         => "Gavekort",
diff --git a/app/Language/de-CH/Sales.php b/app/Language/de-CH/Sales.php
index 32d1cc228..e23ad70ce 100644
--- a/app/Language/de-CH/Sales.php
+++ b/app/Language/de-CH/Sales.php
@@ -73,6 +73,12 @@ return [
     "employee"                         => "Mitarbeiter",
     "entry"                            => "",
     "error_editing_item"               => "Fehler beim Ändern des Artikels",
+    "negative_price_invalid"           => "",
+    "negative_quantity_invalid"        => "",
+    "negative_discount_invalid"        => "",
+    "discount_percent_exceeds_100"     => "",
+    "discount_exceeds_item_total"      => "",
+    "negative_total_invalid"           => "",
     "find_or_scan_item"                => "Finde/Scanne Artikel",
     "find_or_scan_item_or_receipt"     => "Finde/Scanne Artikel oder Quittung",
     "giftcard"                         => "Gutschein",
diff --git a/app/Language/de-DE/Sales.php b/app/Language/de-DE/Sales.php
index 198ff239f..1cad8dc35 100644
--- a/app/Language/de-DE/Sales.php
+++ b/app/Language/de-DE/Sales.php
@@ -73,6 +73,12 @@ return [
     "employee"                         => "Mitarbeiter",
     "entry"                            => "Eintrag",
     "error_editing_item"               => "Fehler beim Ändern des Artikels",
+    "negative_price_invalid"           => "",
+    "negative_quantity_invalid"        => "",
+    "negative_discount_invalid"        => "",
+    "discount_percent_exceeds_100"     => "",
+    "discount_exceeds_item_total"      => "",
+    "negative_total_invalid"           => "",
     "find_or_scan_item"                => "Finde/Scanne Artikel",
     "find_or_scan_item_or_receipt"     => "Finde/Scanne Artikel oder Quittung",
     "giftcard"                         => "Gutschein",
diff --git a/app/Language/el/Sales.php b/app/Language/el/Sales.php
index 90dd0d5d0..867213f70 100644
--- a/app/Language/el/Sales.php
+++ b/app/Language/el/Sales.php
@@ -73,6 +73,12 @@ return [
     "employee"                         => "Υπάλληλος",
     "entry"                            => "Εγγραφή",
     "error_editing_item"               => "Σφάλμα επεξεργασίας είδους",
+    "negative_price_invalid"           => "",
+    "negative_quantity_invalid"        => "",
+    "negative_discount_invalid"        => "",
+    "discount_percent_exceeds_100"     => "",
+    "discount_exceeds_item_total"      => "",
+    "negative_total_invalid"           => "",
     "find_or_scan_item"                => "Εύρεση ή Σκανάρισμα Είδους",
     "find_or_scan_item_or_receipt"     => "Εύρεση ή Σκανάρισμα είδους ή Απόδειξης",
     "giftcard"                         => "Δωροκάρτα",
diff --git a/app/Language/en-GB/Sales.php b/app/Language/en-GB/Sales.php
index d9678ba44..f68d14d45 100644
--- a/app/Language/en-GB/Sales.php
+++ b/app/Language/en-GB/Sales.php
@@ -73,6 +73,12 @@ return [
     "employee"                         => "Employee",
     "entry"                            => "Entry",
     "error_editing_item"               => "Error editing item",
+    "negative_price_invalid"           => "Price cannot be negative.",
+    "negative_quantity_invalid"        => "Quantity cannot be negative.",
+    "negative_discount_invalid"        => "Discount cannot be negative.",
+    "discount_percent_exceeds_100"     => "Percentage discount cannot exceed 100%.",
+    "discount_exceeds_item_total"      => "Discount cannot exceed the item total.",
+    "negative_total_invalid"           => "Sale total cannot be negative. Check item discounts and quantities.",
     "find_or_scan_item"                => "Find or Scan Item",
     "find_or_scan_item_or_receipt"     => "Find or Scan Item or Receipt",
     "giftcard"                         => "Gift Card",
diff --git a/app/Language/en/Sales.php b/app/Language/en/Sales.php
index 6c7d93d48..c16c345b4 100644
--- a/app/Language/en/Sales.php
+++ b/app/Language/en/Sales.php
@@ -73,6 +73,12 @@ return [
     "employee"                         => "Employee",
     "entry"                            => "Entry",
     "error_editing_item"               => "Error editing item",
+    "negative_price_invalid"           => "Price cannot be negative.",
+    "negative_quantity_invalid"        => "Quantity cannot be negative.",
+    "negative_discount_invalid"        => "Discount cannot be negative.",
+    "discount_percent_exceeds_100"     => "Percentage discount cannot exceed 100%.",
+    "discount_exceeds_item_total"      => "Discount cannot exceed the item total.",
+    "negative_total_invalid"           => "Sale total cannot be negative. Check item discounts and quantities.",
     "find_or_scan_item"                => "Find or Scan Item",
     "find_or_scan_item_or_receipt"     => "Find or Scan Item or Receipt",
     "giftcard"                         => "Gift Card",
diff --git a/app/Language/es-ES/Sales.php b/app/Language/es-ES/Sales.php
index a337f7539..9e5f710d7 100644
--- a/app/Language/es-ES/Sales.php
+++ b/app/Language/es-ES/Sales.php
@@ -73,6 +73,12 @@ return [
     "employee"                         => "Empleado",
     "entry"                            => "Entrada",
     "error_editing_item"               => "Error editando artículo",
+    "negative_price_invalid"           => "",
+    "negative_quantity_invalid"        => "",
+    "negative_discount_invalid"        => "",
+    "discount_percent_exceeds_100"     => "",
+    "discount_exceeds_item_total"      => "",
+    "negative_total_invalid"           => "",
     "find_or_scan_item"                => "Encontrar/Escanear Artículo",
     "find_or_scan_item_or_receipt"     => "Encontrar/Escanear Artículo o Entrada",
     "giftcard"                         => "Tarjeta de Regalo",
diff --git a/app/Language/es-MX/Sales.php b/app/Language/es-MX/Sales.php
index b0e521c5b..9295d2e36 100644
--- a/app/Language/es-MX/Sales.php
+++ b/app/Language/es-MX/Sales.php
@@ -73,6 +73,12 @@ return [
     "employee"                         => "Empleado",
     "entry"                            => "Entrada",
     "error_editing_item"               => "Error editando el artículo",
+    "negative_price_invalid"           => "",
+    "negative_quantity_invalid"        => "",
+    "negative_discount_invalid"        => "",
+    "discount_percent_exceeds_100"     => "",
+    "discount_exceeds_item_total"      => "",
+    "negative_total_invalid"           => "",
     "find_or_scan_item"                => "Buscar o escanear artículo",
     "find_or_scan_item_or_receipt"     => "Buscar o escanear artículo o recibo",
     "giftcard"                         => "Tarjeta de regalo",
diff --git a/app/Language/fa/Sales.php b/app/Language/fa/Sales.php
index 182a534e2..2ea23afcc 100644
--- a/app/Language/fa/Sales.php
+++ b/app/Language/fa/Sales.php
@@ -73,6 +73,12 @@ return [
     "employee"                         => "کارمند",
     "entry"                            => "ورود",
     "error_editing_item"               => "خطا در ویرایش مورد",
+    "negative_price_invalid"           => "",
+    "negative_quantity_invalid"        => "",
+    "negative_discount_invalid"        => "",
+    "discount_percent_exceeds_100"     => "",
+    "discount_exceeds_item_total"      => "",
+    "negative_total_invalid"           => "",
     "find_or_scan_item"                => "یافتن یا اسکن کردن مورد",
     "find_or_scan_item_or_receipt"     => "یافتن یا اسکن کردن مورد یا رسید",
     "giftcard"                         => "کارت هدیه",
diff --git a/app/Language/fr/Sales.php b/app/Language/fr/Sales.php
index 34caae2f4..5fa816844 100644
--- a/app/Language/fr/Sales.php
+++ b/app/Language/fr/Sales.php
@@ -73,6 +73,12 @@ return [
     "employee"                         => "Employé",
     "entry"                            => "Entrée",
     "error_editing_item"               => "Érreur lors de l'édition",
+    "negative_price_invalid"           => "",
+    "negative_quantity_invalid"        => "",
+    "negative_discount_invalid"        => "",
+    "discount_percent_exceeds_100"     => "",
+    "discount_exceeds_item_total"      => "",
+    "negative_total_invalid"           => "",
     "find_or_scan_item"                => "Trouver/Scanner Article",
     "find_or_scan_item_or_receipt"     => "Trouver/Scanner Article OU Reçu",
     "giftcard"                         => "Carte Cadeau",
diff --git a/app/Language/he/Sales.php b/app/Language/he/Sales.php
index f2bd399ba..2aa19d64c 100644
--- a/app/Language/he/Sales.php
+++ b/app/Language/he/Sales.php
@@ -73,6 +73,12 @@ return [
     "employee"                         => "עובד",
     "entry"                            => "ערך",
     "error_editing_item"               => "שגיאה בעריכת פריט",
+    "negative_price_invalid"           => "",
+    "negative_quantity_invalid"        => "",
+    "negative_discount_invalid"        => "",
+    "discount_percent_exceeds_100"     => "",
+    "discount_exceeds_item_total"      => "",
+    "negative_total_invalid"           => "",
     "find_or_scan_item"                => "חיפוש או סריקה של פריט",
     "find_or_scan_item_or_receipt"     => "חיפוש או סריקה של פריט או קבלה",
     "giftcard"                         => "כרטיס מתנה",
diff --git a/app/Language/hr-HR/Sales.php b/app/Language/hr-HR/Sales.php
index 9e2df3b99..fed22729d 100644
--- a/app/Language/hr-HR/Sales.php
+++ b/app/Language/hr-HR/Sales.php
@@ -73,6 +73,12 @@ return [
     "employee"                         => "Radnik",
     "entry"                            => "",
     "error_editing_item"               => "Greška kod uređivanja artikla",
+    "negative_price_invalid"           => "",
+    "negative_quantity_invalid"        => "",
+    "negative_discount_invalid"        => "",
+    "discount_percent_exceeds_100"     => "",
+    "discount_exceeds_item_total"      => "",
+    "negative_total_invalid"           => "",
     "find_or_scan_item"                => "Pronađi/Skaniraj artikal",
     "find_or_scan_item_or_receipt"     => "Pronađi/Skaniraj artikal ili račun",
     "giftcard"                         => "Poklon bon",
diff --git a/app/Language/hu/Sales.php b/app/Language/hu/Sales.php
index 5928b2708..a864dd1af 100644
--- a/app/Language/hu/Sales.php
+++ b/app/Language/hu/Sales.php
@@ -73,6 +73,12 @@ return [
     "employee"                         => "Dolgozó",
     "entry"                            => "",
     "error_editing_item"               => "Termék módositási hiba",
+    "negative_price_invalid"           => "",
+    "negative_quantity_invalid"        => "",
+    "negative_discount_invalid"        => "",
+    "discount_percent_exceeds_100"     => "",
+    "discount_exceeds_item_total"      => "",
+    "negative_total_invalid"           => "",
     "find_or_scan_item"                => "Termék keresés/scan",
     "find_or_scan_item_or_receipt"     => "Termék keresése",
     "giftcard"                         => "Ajándék utalvány",
diff --git a/app/Language/hy/Sales.php b/app/Language/hy/Sales.php
index b38f57446..bf138169a 100644
--- a/app/Language/hy/Sales.php
+++ b/app/Language/hy/Sales.php
@@ -73,6 +73,12 @@ return [
     "employee"                         => "",
     "entry"                            => "",
     "error_editing_item"               => "",
+    "negative_price_invalid"           => "",
+    "negative_quantity_invalid"        => "",
+    "negative_discount_invalid"        => "",
+    "discount_percent_exceeds_100"     => "",
+    "discount_exceeds_item_total"      => "",
+    "negative_total_invalid"           => "",
     "find_or_scan_item"                => "",
     "find_or_scan_item_or_receipt"     => "",
     "giftcard"                         => "",
diff --git a/app/Language/id/Sales.php b/app/Language/id/Sales.php
index e15191351..555ad5076 100644
--- a/app/Language/id/Sales.php
+++ b/app/Language/id/Sales.php
@@ -73,6 +73,12 @@ return [
     "employee"                         => "Karyawan",
     "entry"                            => "Entri",
     "error_editing_item"               => "mengubah item salah",
+    "negative_price_invalid"           => "",
+    "negative_quantity_invalid"        => "",
+    "negative_discount_invalid"        => "",
+    "discount_percent_exceeds_100"     => "",
+    "discount_exceeds_item_total"      => "",
+    "negative_total_invalid"           => "",
     "find_or_scan_item"                => "Cari/Scan Item",
     "find_or_scan_item_or_receipt"     => "Temukan atau pindai Item atau Faktur",
     "giftcard"                         => "Kartu Hadiah",
diff --git a/app/Language/it/Sales.php b/app/Language/it/Sales.php
index 84d9a65a2..39f32a770 100644
--- a/app/Language/it/Sales.php
+++ b/app/Language/it/Sales.php
@@ -73,6 +73,12 @@ return [
     "employee"                         => "Impiegato",
     "entry"                            => "Voce",
     "error_editing_item"               => "Errore modificando un articolo",
+    "negative_price_invalid"           => "",
+    "negative_quantity_invalid"        => "",
+    "negative_discount_invalid"        => "",
+    "discount_percent_exceeds_100"     => "",
+    "discount_exceeds_item_total"      => "",
+    "negative_total_invalid"           => "",
     "find_or_scan_item"                => "Scansiona o Cerca Articolo",
     "find_or_scan_item_or_receipt"     => "Scansiona o Cerca Articolo o Scontrino",
     "giftcard"                         => "Carta Regalo",
diff --git a/app/Language/km/Sales.php b/app/Language/km/Sales.php
index 8fd15efb4..0c43ea100 100644
--- a/app/Language/km/Sales.php
+++ b/app/Language/km/Sales.php
@@ -73,6 +73,12 @@ return [
     "employee"                         => "បុគ្គលិក",
     "entry"                            => "បញ្ចូល",
     "error_editing_item"               => "មានកំហុស ក្នុងការកែប្រែទំនិញ",
+    "negative_price_invalid"           => "",
+    "negative_quantity_invalid"        => "",
+    "negative_discount_invalid"        => "",
+    "discount_percent_exceeds_100"     => "",
+    "discount_exceeds_item_total"      => "",
+    "negative_total_invalid"           => "",
     "find_or_scan_item"                => "ស្វែងរក ឬស្កេនទំនិញ",
     "find_or_scan_item_or_receipt"     => "ស្វែងរក ឬ​ស្កេនទំនិញ ឬ វិក័យបត្រ",
     "giftcard"                         => "កាតអំណោយ",
diff --git a/app/Language/lo/Sales.php b/app/Language/lo/Sales.php
index 66745059f..49b748b3d 100644
--- a/app/Language/lo/Sales.php
+++ b/app/Language/lo/Sales.php
@@ -73,6 +73,12 @@ return [
     "employee"                         => "Employee",
     "entry"                            => "Entry",
     "error_editing_item"               => "Error editing item",
+    "negative_price_invalid"           => "",
+    "negative_quantity_invalid"        => "",
+    "negative_discount_invalid"        => "",
+    "discount_percent_exceeds_100"     => "",
+    "discount_exceeds_item_total"      => "",
+    "negative_total_invalid"           => "",
     "find_or_scan_item"                => "Find or Scan Item",
     "find_or_scan_item_or_receipt"     => "Find or Scan Item or Receipt",
     "giftcard"                         => "Gift Card",
diff --git a/app/Language/ml/Sales.php b/app/Language/ml/Sales.php
index f8397f233..4bda63368 100644
--- a/app/Language/ml/Sales.php
+++ b/app/Language/ml/Sales.php
@@ -73,6 +73,12 @@ return [
     "employee"                         => "",
     "entry"                            => "",
     "error_editing_item"               => "",
+    "negative_price_invalid"           => "",
+    "negative_quantity_invalid"        => "",
+    "negative_discount_invalid"        => "",
+    "discount_percent_exceeds_100"     => "",
+    "discount_exceeds_item_total"      => "",
+    "negative_total_invalid"           => "",
     "find_or_scan_item"                => "",
     "find_or_scan_item_or_receipt"     => "",
     "giftcard"                         => "",
diff --git a/app/Language/nb/Sales.php b/app/Language/nb/Sales.php
index b38f57446..bf138169a 100644
--- a/app/Language/nb/Sales.php
+++ b/app/Language/nb/Sales.php
@@ -73,6 +73,12 @@ return [
     "employee"                         => "",
     "entry"                            => "",
     "error_editing_item"               => "",
+    "negative_price_invalid"           => "",
+    "negative_quantity_invalid"        => "",
+    "negative_discount_invalid"        => "",
+    "discount_percent_exceeds_100"     => "",
+    "discount_exceeds_item_total"      => "",
+    "negative_total_invalid"           => "",
     "find_or_scan_item"                => "",
     "find_or_scan_item_or_receipt"     => "",
     "giftcard"                         => "",
diff --git a/app/Language/nl-BE/Sales.php b/app/Language/nl-BE/Sales.php
index f2768e8ed..a287c0d62 100644
--- a/app/Language/nl-BE/Sales.php
+++ b/app/Language/nl-BE/Sales.php
@@ -73,6 +73,12 @@ return [
     "employee"                         => "Werknemer",
     "entry"                            => "Rij",
     "error_editing_item"               => "Fout bij bewerken",
+    "negative_price_invalid"           => "",
+    "negative_quantity_invalid"        => "",
+    "negative_discount_invalid"        => "",
+    "discount_percent_exceeds_100"     => "",
+    "discount_exceeds_item_total"      => "",
+    "negative_total_invalid"           => "",
     "find_or_scan_item"                => "Zoek/Scan Product",
     "find_or_scan_item_or_receipt"     => "Zoek/Scan Product of Ticket",
     "giftcard"                         => "Cadeaubon",
diff --git a/app/Language/nl-NL/Sales.php b/app/Language/nl-NL/Sales.php
index e37c31c23..12826cc27 100644
--- a/app/Language/nl-NL/Sales.php
+++ b/app/Language/nl-NL/Sales.php
@@ -73,6 +73,12 @@ return [
     "employee"                         => "Werknemer",
     "entry"                            => "Vermelding",
     "error_editing_item"               => "Fout bij artikel bewerken",
+    "negative_price_invalid"           => "",
+    "negative_quantity_invalid"        => "",
+    "negative_discount_invalid"        => "",
+    "discount_percent_exceeds_100"     => "",
+    "discount_exceeds_item_total"      => "",
+    "negative_total_invalid"           => "",
     "find_or_scan_item"                => "Artikel zoeken of scannen",
     "find_or_scan_item_or_receipt"     => "Artikel of kassabon vinden of scannen",
     "giftcard"                         => "Cadeaubon",
diff --git a/app/Language/pl/Sales.php b/app/Language/pl/Sales.php
index 3a5515cf5..170380a7d 100644
--- a/app/Language/pl/Sales.php
+++ b/app/Language/pl/Sales.php
@@ -73,6 +73,12 @@ return [
     'employee' => "",
     'entry' => "",
     'error_editing_item' => "",
+    "negative_price_invalid"           => "",
+    "negative_quantity_invalid"        => "",
+    "negative_discount_invalid"        => "",
+    "discount_percent_exceeds_100"     => "",
+    "discount_exceeds_item_total"      => "",
+    "negative_total_invalid"           => "",
     'find_or_scan_item' => "",
     'find_or_scan_item_or_receipt' => "",
     'giftcard' => "Karta Podarunkowa",
diff --git a/app/Language/pt-BR/Sales.php b/app/Language/pt-BR/Sales.php
index 5f87ba959..479c72d3a 100644
--- a/app/Language/pt-BR/Sales.php
+++ b/app/Language/pt-BR/Sales.php
@@ -73,6 +73,12 @@ return [
     "employee"                         => "Empregado",
     "entry"                            => "Entrada",
     "error_editing_item"               => "Erro editando item",
+    "negative_price_invalid"           => "",
+    "negative_quantity_invalid"        => "",
+    "negative_discount_invalid"        => "",
+    "discount_percent_exceeds_100"     => "",
+    "discount_exceeds_item_total"      => "",
+    "negative_total_invalid"           => "",
     "find_or_scan_item"                => "Pesquisar Item",
     "find_or_scan_item_or_receipt"     => "Produto",
     "giftcard"                         => "Cupom",
diff --git a/app/Language/ro/Sales.php b/app/Language/ro/Sales.php
index 815b1176d..4370f287a 100644
--- a/app/Language/ro/Sales.php
+++ b/app/Language/ro/Sales.php
@@ -73,6 +73,12 @@ return [
     "employee"                         => "Salariat",
     "entry"                            => "Intrare",
     "error_editing_item"               => "Eroare editare articol",
+    "negative_price_invalid"           => "",
+    "negative_quantity_invalid"        => "",
+    "negative_discount_invalid"        => "",
+    "discount_percent_exceeds_100"     => "",
+    "discount_exceeds_item_total"      => "",
+    "negative_total_invalid"           => "",
     "find_or_scan_item"                => "Gaseste sau scaneaza Articol",
     "find_or_scan_item_or_receipt"     => "Gaseste sau scaneaza Articol sau Chitanta",
     "giftcard"                         => "Card Cadou",
diff --git a/app/Language/ru/Sales.php b/app/Language/ru/Sales.php
index 7a3c2a977..a26160981 100644
--- a/app/Language/ru/Sales.php
+++ b/app/Language/ru/Sales.php
@@ -73,6 +73,12 @@ return [
     "employee"                         => "Сотрудник",
     "entry"                            => "Запись",
     "error_editing_item"               => "Ошибка при редактировании товара",
+    "negative_price_invalid"           => "",
+    "negative_quantity_invalid"        => "",
+    "negative_discount_invalid"        => "",
+    "discount_percent_exceeds_100"     => "",
+    "discount_exceeds_item_total"      => "",
+    "negative_total_invalid"           => "",
     "find_or_scan_item"                => "Найти/Сканировать товар",
     "find_or_scan_item_or_receipt"     => "Найти/Сканировать товара или квитанцию",
     "giftcard"                         => "Подарочная карта",
diff --git a/app/Language/sv/Sales.php b/app/Language/sv/Sales.php
index b492a389f..697668945 100644
--- a/app/Language/sv/Sales.php
+++ b/app/Language/sv/Sales.php
@@ -73,6 +73,12 @@ return [
     "employee"                         => "Anställd",
     "entry"                            => "Post",
     "error_editing_item"               => "Ändra artikel misslyckades",
+    "negative_price_invalid"           => "",
+    "negative_quantity_invalid"        => "",
+    "negative_discount_invalid"        => "",
+    "discount_percent_exceeds_100"     => "",
+    "discount_exceeds_item_total"      => "",
+    "negative_total_invalid"           => "",
     "find_or_scan_item"                => "Hitta eller skanna artikel",
     "find_or_scan_item_or_receipt"     => "Hitta eller skanna artikel eller kvitto",
     "giftcard"                         => "Presentkort",
diff --git a/app/Language/sw-KE/Sales.php b/app/Language/sw-KE/Sales.php
index 2dc789bda..6748f957b 100644
--- a/app/Language/sw-KE/Sales.php
+++ b/app/Language/sw-KE/Sales.php
@@ -73,6 +73,12 @@ return [
     "employee"                         => "Mfanyakazi",
     "entry"                            => "Ingizo",
     "error_editing_item"               => "Hitilafu katika kuhariri bidhaa",
+    "negative_price_invalid"           => "",
+    "negative_quantity_invalid"        => "",
+    "negative_discount_invalid"        => "",
+    "discount_percent_exceeds_100"     => "",
+    "discount_exceeds_item_total"      => "",
+    "negative_total_invalid"           => "",
     "find_or_scan_item"                => "Tafuta au Changanua Bidhaa",
     "find_or_scan_item_or_receipt"     => "Tafuta au Changanua Bidhaa au Risiti",
     "giftcard"                         => "Kadi ya Zawadi",
diff --git a/app/Language/sw-TZ/Sales.php b/app/Language/sw-TZ/Sales.php
index 2dc789bda..6748f957b 100644
--- a/app/Language/sw-TZ/Sales.php
+++ b/app/Language/sw-TZ/Sales.php
@@ -73,6 +73,12 @@ return [
     "employee"                         => "Mfanyakazi",
     "entry"                            => "Ingizo",
     "error_editing_item"               => "Hitilafu katika kuhariri bidhaa",
+    "negative_price_invalid"           => "",
+    "negative_quantity_invalid"        => "",
+    "negative_discount_invalid"        => "",
+    "discount_percent_exceeds_100"     => "",
+    "discount_exceeds_item_total"      => "",
+    "negative_total_invalid"           => "",
     "find_or_scan_item"                => "Tafuta au Changanua Bidhaa",
     "find_or_scan_item_or_receipt"     => "Tafuta au Changanua Bidhaa au Risiti",
     "giftcard"                         => "Kadi ya Zawadi",
diff --git a/app/Language/ta/Sales.php b/app/Language/ta/Sales.php
index c1611c31e..4019e1012 100644
--- a/app/Language/ta/Sales.php
+++ b/app/Language/ta/Sales.php
@@ -73,6 +73,12 @@ return [
     "employee"                         => "ஊழியர்",
     "entry"                            => "உள்ளீடு",
     "error_editing_item"               => "பொருளை திருத்துவதில் பிழை",
+    "negative_price_invalid"           => "",
+    "negative_quantity_invalid"        => "",
+    "negative_discount_invalid"        => "",
+    "discount_percent_exceeds_100"     => "",
+    "discount_exceeds_item_total"      => "",
+    "negative_total_invalid"           => "",
     "find_or_scan_item"                => "பொருளைக் தேடு அல்லது ஸ்கேன் செய்யுங்கள்",
     "find_or_scan_item_or_receipt"     => "தேடு அல்லது பொருளை வருடு அல்லது ரசீது",
     "giftcard"                         => "பரிசு அட்டை",
diff --git a/app/Language/th/Sales.php b/app/Language/th/Sales.php
index 0a8ec17b1..764f949d8 100644
--- a/app/Language/th/Sales.php
+++ b/app/Language/th/Sales.php
@@ -73,6 +73,12 @@ return [
     "employee"                         => "พนักงาน",
     "entry"                            => "การนำเข้า",
     "error_editing_item"               => "แก้ไขสินค้าล้มเหลว",
+    "negative_price_invalid"           => "",
+    "negative_quantity_invalid"        => "",
+    "negative_discount_invalid"        => "",
+    "discount_percent_exceeds_100"     => "",
+    "discount_exceeds_item_total"      => "",
+    "negative_total_invalid"           => "",
     "find_or_scan_item"                => "ค้นหาสินค้า",
     "find_or_scan_item_or_receipt"     => "ค้นหา หรือ แสกนรายการ หรือ ใบเสร็จ",
     "giftcard"                         => "บัตรของขวัญ",
diff --git a/app/Language/tl/Sales.php b/app/Language/tl/Sales.php
index 3cb4d1653..a40e655db 100644
--- a/app/Language/tl/Sales.php
+++ b/app/Language/tl/Sales.php
@@ -73,6 +73,12 @@ return [
     "employee"                         => "Employee",
     "entry"                            => "Entry",
     "error_editing_item"               => "Error editing item",
+    "negative_price_invalid"           => "",
+    "negative_quantity_invalid"        => "",
+    "negative_discount_invalid"        => "",
+    "discount_percent_exceeds_100"     => "",
+    "discount_exceeds_item_total"      => "",
+    "negative_total_invalid"           => "",
     "find_or_scan_item"                => "Find or Scan Item",
     "find_or_scan_item_or_receipt"     => "Find or Scan Item or Receipt",
     "giftcard"                         => "Gift Card",
diff --git a/app/Language/tr/Sales.php b/app/Language/tr/Sales.php
index 8901fa02f..48a1ee668 100644
--- a/app/Language/tr/Sales.php
+++ b/app/Language/tr/Sales.php
@@ -73,6 +73,12 @@ return [
     "employee"                         => "Personel",
     "entry"                            => "Girdi",
     "error_editing_item"               => "Ürün düzenleme hatası",
+    "negative_price_invalid"           => "",
+    "negative_quantity_invalid"        => "",
+    "negative_discount_invalid"        => "",
+    "discount_percent_exceeds_100"     => "",
+    "discount_exceeds_item_total"      => "",
+    "negative_total_invalid"           => "",
     "find_or_scan_item"                => "Ürün Bul/Oku",
     "find_or_scan_item_or_receipt"     => "Ürün yada Fiş Bul/Oku",
     "giftcard"                         => "Hediye Çeki",
diff --git a/app/Language/uk/Sales.php b/app/Language/uk/Sales.php
index 2524d3a3d..67eabdd5f 100644
--- a/app/Language/uk/Sales.php
+++ b/app/Language/uk/Sales.php
@@ -73,6 +73,12 @@ return [
     "employee"                         => "Працівник",
     "entry"                            => "Вхід",
     "error_editing_item"               => "Помилка редагування товару",
+    "negative_price_invalid"           => "",
+    "negative_quantity_invalid"        => "",
+    "negative_discount_invalid"        => "",
+    "discount_percent_exceeds_100"     => "",
+    "discount_exceeds_item_total"      => "",
+    "negative_total_invalid"           => "",
     "find_or_scan_item"                => "Знайти/Сканувати товар",
     "find_or_scan_item_or_receipt"     => "Знайти/Сканувати товар або квитанцію",
     "giftcard"                         => "Подарункова карта",
diff --git a/app/Language/ur/Sales.php b/app/Language/ur/Sales.php
index 16f3d32e4..6ee0bae6d 100644
--- a/app/Language/ur/Sales.php
+++ b/app/Language/ur/Sales.php
@@ -73,6 +73,12 @@ return [
     "employee"                         => "",
     "entry"                            => "",
     "error_editing_item"               => "",
+    "negative_price_invalid"           => "",
+    "negative_quantity_invalid"        => "",
+    "negative_discount_invalid"        => "",
+    "discount_percent_exceeds_100"     => "",
+    "discount_exceeds_item_total"      => "",
+    "negative_total_invalid"           => "",
     "find_or_scan_item"                => "",
     "find_or_scan_item_or_receipt"     => "",
     "giftcard"                         => "",
diff --git a/app/Language/vi/Sales.php b/app/Language/vi/Sales.php
index d99083c28..9d65ddaeb 100644
--- a/app/Language/vi/Sales.php
+++ b/app/Language/vi/Sales.php
@@ -73,6 +73,12 @@ return [
     "employee"                         => "Nhân viên",
     "entry"                            => "Mục nhập",
     "error_editing_item"               => "Lỗi sửa hàng hóa",
+    "negative_price_invalid"           => "",
+    "negative_quantity_invalid"        => "",
+    "negative_discount_invalid"        => "",
+    "discount_percent_exceeds_100"     => "",
+    "discount_exceeds_item_total"      => "",
+    "negative_total_invalid"           => "",
     "find_or_scan_item"                => "Tìm hay quét Hàng hóa",
     "find_or_scan_item_or_receipt"     => "Tìm hay quét Hàng hóa hay Biên lai",
     "giftcard"                         => "Thẻ quà tặng",
diff --git a/app/Language/zh-Hans/Sales.php b/app/Language/zh-Hans/Sales.php
index 4e04d3d09..ba4df4c6c 100644
--- a/app/Language/zh-Hans/Sales.php
+++ b/app/Language/zh-Hans/Sales.php
@@ -73,6 +73,12 @@ return [
     "employee"                         => "員工",
     "entry"                            => "",
     "error_editing_item"               => "編輯產品錯誤",
+    "negative_price_invalid"           => "",
+    "negative_quantity_invalid"        => "",
+    "negative_discount_invalid"        => "",
+    "discount_percent_exceeds_100"     => "",
+    "discount_exceeds_item_total"      => "",
+    "negative_total_invalid"           => "",
     "find_or_scan_item"                => "查找/掃描商品",
     "find_or_scan_item_or_receipt"     => "查找/掃描產品或收貨單",
     "giftcard"                         => "禮金券",
diff --git a/app/Language/zh-Hant/Sales.php b/app/Language/zh-Hant/Sales.php
index cb1af0dfb..f7e78496d 100644
--- a/app/Language/zh-Hant/Sales.php
+++ b/app/Language/zh-Hant/Sales.php
@@ -73,6 +73,12 @@ return [
     "employee"                         => "員工",
     "entry"                            => "加入項目",
     "error_editing_item"               => "編輯產品錯誤",
+    "negative_price_invalid"           => "",
+    "negative_quantity_invalid"        => "",
+    "negative_discount_invalid"        => "",
+    "discount_percent_exceeds_100"     => "",
+    "discount_exceeds_item_total"      => "",
+    "negative_total_invalid"           => "",
     "find_or_scan_item"                => "查找/掃描商品",
     "find_or_scan_item_or_receipt"     => "查找/掃描產品或收貨單",
     "giftcard"                         => "禮金券",