Comment by AnotherGoodName

Ooooh do the one where hitting ‘payment’ on the app buys $25 of store credit by default rather than just paying and deducts the 9.64 from that credit.

Then when you spend down the credit to $2 any attempt to buy something that costs more refills the credit.

Starbucks app btw. You have to specifically pay with card on the payment screen to avoid buying credit and paying as above.