diff --git a/project/tests/services/PaymentService.test.ts b/project/tests/services/PaymentService.test.ts
index 52817c1c..6884f663 100644
--- a/project/tests/services/PaymentService.test.ts
+++ b/project/tests/services/PaymentService.test.ts
@@ -14,7 +14,7 @@ import { Item } from "@spt-aki/models/eft/common/tables/IItem";
 
 describe("PaymentService", () =>
 {
-    let paymentService: PaymentService;
+    let paymentService: any; // Using "any" to access private/protected methods without type errors.
 
     beforeAll(() =>
     {
@@ -143,4 +143,97 @@ describe("PaymentService", () =>
             expect(traderHelperLvlUpSpy).toBeCalledTimes(1);
         });
     });
+
+    describe("isInStash", () =>
+    {
+        it("should return true when item is direct parent of stash", () =>
+        {
+            const hashUtil = container.resolve<HashUtil>("HashUtil");
+            const stashItem: Item = {
+                _id: "stashid",
+                _tpl: "55d7217a4bdc2d86028b456d" // standard stash id
+            };
+
+            const inventoryItemToFind: Item = {
+                _id: hashUtil.generate(),
+                _tpl: "544fb6cc4bdc2d34748b456e", // Slickers chocolate bar
+                parentId: stashItem._id,
+                slotId: "hideout"
+            };
+            const playerInventory = [stashItem, inventoryItemToFind];
+
+            const result = paymentService.isInStash(inventoryItemToFind._id, playerInventory, stashItem._id);
+
+            expect(result).toBe(true);
+        });
+
+        it("should return true when item is indirect parent of inventory", () =>
+        {
+            const hashUtil = container.resolve<HashUtil>("HashUtil");
+            const stashItem: Item = {
+                _id: "stashId",
+                _tpl: "55d7217a4bdc2d86028b456d" // standard stash id
+            };
+
+            const foodBagToHoldItemToFind: Item = {
+                _id: hashUtil.generate(),
+                _tpl: "5c093db286f7740a1b2617e3",
+                parentId: stashItem._id,
+                slotId: "hideout"
+            };
+
+            const inventoryItemToFind: Item = {
+                _id: hashUtil.generate(),
+                _tpl: "544fb6cc4bdc2d34748b456e", // Slickers chocolate bar
+                parentId: foodBagToHoldItemToFind._id
+            };
+            const playerInventory = [stashItem, foodBagToHoldItemToFind, inventoryItemToFind];
+
+            const result = paymentService.isInStash(inventoryItemToFind._id, playerInventory, stashItem._id);
+
+            expect(result).toBe(true);
+        });
+
+        it("should return false when desired item is not in inventory", () =>
+        {
+            const hashUtil = container.resolve<HashUtil>("HashUtil");
+            const stashItem: Item = {
+                _id: "stashId",
+                _tpl: "55d7217a4bdc2d86028b456d" // standard stash id
+            };
+
+            const inventoryItemToFind: Item = {
+                _id: hashUtil.generate(),
+                _tpl: "544fb6cc4bdc2d34748b456e", // Slickers chocolate bar
+                parentId: stashItem._id,
+                slotId: "hideout"
+            };
+            const playerInventory = [stashItem, inventoryItemToFind];
+
+            const result = paymentService.isInStash("notCorrectId", playerInventory, stashItem._id);
+
+            expect(result).toBe(false);
+        });
+
+        it("should return false when player inventory array has no inventory item", () =>
+        {
+            const hashUtil = container.resolve<HashUtil>("HashUtil");
+            const stashItem: Item = {
+                _id: "stashId",
+                _tpl: "55d7217a4bdc2d86028b456d" // standard stash id
+            };
+
+            const inventoryItemToFind: Item = {
+                _id: hashUtil.generate(),
+                _tpl: "544fb6cc4bdc2d34748b456e", // Slickers chocolate bar
+                parentId: stashItem._id,
+                slotId: "hideout"
+            };
+            const playerInventory = [ inventoryItemToFind];
+
+            const result = paymentService.isInStash("notCorrectId", playerInventory, stashItem._id);
+
+            expect(result).toBe(false);
+        });
+    });
 });