As a way of rewarding their customers or to say encouraging them to use their credit cards, banks offer cash back. This is usually a percentage of the amount you spend through your card and it is credited to your account at the end of the billing cycle. The rates of the cash back percentage can vary but usually they are around 1 to 2%. Some banks even go higher with 5% cash back.
You must look for the best cash back card as this could be a way of saving a lot of money if you always use your credit card for making various payments.