fix

lib/api.dart

@@ -201,7 +201,7 @@ class API {
 
   // /demand
   Future<void> consumeItem(
-      String transaction, String destination, String price) async {
+      String transaction, String destination, double price) async {
     await postRequest("$instance/demand",
         {"uuid": transaction, "destination": destination, "price": price});
   }

lib/pages/consume.dart

@@ -27,8 +27,8 @@ class _ConsumePageState extends State<ConsumePage> {
       _formKey.currentState!.save();
 
       API()
-          .consumeItem(
-              widget.transaction.uuid, _selectedDestination, "$_price €")
+          .consumeItem(widget.transaction.uuid, _selectedDestination,
+              double.parse(_price))
           .then((_) {
         ScaffoldMessenger.of(context).showSnackBar(
           const SnackBar(content: Text('Item consumed successfully!')),