diff --git a/Server/src/main/content/minigame/vinesweeper/Vinesweeper.kt b/Server/src/main/content/minigame/vinesweeper/Vinesweeper.kt
index 04fe7686a..09e126d6a 100644
--- a/Server/src/main/content/minigame/vinesweeper/Vinesweeper.kt
+++ b/Server/src/main/content/minigame/vinesweeper/Vinesweeper.kt
@@ -73,8 +73,11 @@ class Vinesweeper : InteractionListener, InterfaceListener, MapArea {
                 }
                 val roots = entity.inventory.getAmount(Item(Items.OGLEROOT_12624))
                 if(roots > 0) {
+                    val refund = calculateExchangeCost(entity, 10, roots, null)
                     entity.inventory.remove(Item(Items.OGLEROOT_12624, roots))
-                    entity.inventory.add(Item(Items.COINS_995, roots * 10))
+                    if(refund != null) {
+                        entity.inventory.add(Item(Items.COINS_995, refund.totalCost))
+                    }
                 }
             }
         }
@@ -332,19 +335,21 @@ class Vinesweeper : InteractionListener, InterfaceListener, MapArea {
 
         fun buy(player: Player, buttonID: Int, amount: Int) {
             val reward = REWARDS[buttonID] ?: return
-            val cost = amount * reward.points
+            val exchange = calculateExchangeCost(player, reward.points, amount, "You don't have enough points for that.") ?: return
             val points = player.getAttribute("vinesweeper:points", 0)
-            if(cost in 1 until points) {
-                val item = Item(reward.itemID, amount)
-                if(!player.inventory.add(item)) {
-                    GroundItemManager.create(item, player)
-                }
-                player.incrementAttribute("/save:vinesweeper:points", -cost)
-                sendUpdatedPoints(player)
-            } else {
-                // TODO (crash): authenticity
+
+            if (points < exchange.totalCost) {
                 player.sendMessage("You don't have enough points for that.")
+                return
             }
+
+            val item = Item(reward.itemID, exchange.amount)
+            if (!player.inventory.add(item)) {
+                GroundItemManager.create(item, player)
+            }
+
+            player.incrementAttribute("/save:vinesweeper:points", -exchange.totalCost)
+            sendUpdatedPoints(player)
         }
 
 
diff --git a/Server/src/main/content/minigame/vinesweeper/VinesweeperDialogues.kt b/Server/src/main/content/minigame/vinesweeper/VinesweeperDialogues.kt
index 23c012487..dbd5c1111 100644
--- a/Server/src/main/content/minigame/vinesweeper/VinesweeperDialogues.kt
+++ b/Server/src/main/content/minigame/vinesweeper/VinesweeperDialogues.kt
@@ -132,12 +132,14 @@ class BlinkinDialogue : FarmerDialogue() {
             42 -> {
                     sendInputDialogue(player!!, InputType.AMOUNT, "Enter an amount:") { value ->
                     val amount = value as Int
-                    val price = Item(Items.COINS_995, 10 * amount)
-                    if(price.amount <= 0){
+                    val exchange = calculateExchangeCost(player!!, 10, amount, null) ?: run {
+                        npcl("Sorry, ya can't afford that many. Come back when yer feeling a bit richer if ya like!")
+                        stage = END_DIALOGUE
                         return@sendInputDialogue
                     }
+                    val price = Item(Items.COINS_995, exchange.totalCost)
                     if(player!!.inventory.containsItem(price) && player!!.inventory.remove(price)) {
-                        if(player!!.inventory.add(Item(Items.OGLEROOT_12624, amount))) {
+                        if(player!!.inventory.add(Item(Items.OGLEROOT_12624, exchange.amount))) {
                             npcl("There ya go! Good luck!")
                             stage = END_DIALOGUE
                         } else {
diff --git a/Server/src/main/core/api/ContentAPI.kt b/Server/src/main/core/api/ContentAPI.kt
index 7423518a7..23494305c 100644
--- a/Server/src/main/core/api/ContentAPI.kt
+++ b/Server/src/main/core/api/ContentAPI.kt
@@ -1054,6 +1054,36 @@ fun openDialogue(player: Player, dialogue: Any, vararg args: Any) {
     }
 }
 
+data class ExchangeAmount(val amount: Int, val totalCost: Int)
+
+/**
+ * Safely calculates the total cost
+ *
+ * Prevents zero, negative, and int-overflow costs before callers remove currency
+ * or add rewards. The cost can be coins, points, tickets, tokul, tokens, etc.
+ *
+ * Returns the amount and total cost, or null if invalid.
+ */
+@JvmOverloads
+fun calculateExchangeCost(player: Player,unitCost: Int,amount: Int,failureMessage: String? = "You don't have enough.",dialogue: Boolean = false): ExchangeAmount? {
+    if (unitCost <= 0 || amount <= 0) {
+        failureMessage?.let {
+            if (dialogue) sendDialogue(player, it) else sendMessage(player, it)
+        }
+        return null
+    }
+
+    val totalCost = unitCost.toLong() * amount.toLong()
+    if (totalCost !in 1..Int.MAX_VALUE) {
+        failureMessage?.let {
+            if (dialogue) sendDialogue(player, it) else sendMessage(player, it)
+        }
+        return null
+    }
+
+    return ExchangeAmount(amount, totalCost.toInt())
+}
+
 /**
  * Closes any opened dialogue.
  */