Most citizens have become accustomed to making our purchases using a bank card. It is a comfortable, easy, fast, and effective system that saves us various hassles or inconveniences: having to find an ATM, always carrying cash, or relying on the establishment we visit to have change available. To the usual advantages, we must now add another additional benefit: the possibility that the amount we have spent returns to our account. This is known as “cashback” (literally, “money back”), a reward formula that, in recent times, has started to gain popularity in some banks and stores.