Hi everyone. I have a question about credit cards?

You are correct, if you pay in full the amount you owe then that is all you pay, no interest. If you do not pay the full amount you are required to pay a minimum amount (usually a very small amount). the bank makes their money off of the people that do not pay their balance in full and pay interest. If you are building credit, use your card for things that you have the cash for. Just for example go and buy groceries for $50 and put it on your card. Then when you get home go on your online banking and pay the $50, or set that aside and wait for your statement to bill you. You use the card and pay it off every time you will never pay interest and you will build your credit :)