The idea of a credit card, is that you can buy things early and only have to pay the rest of it off later. You can pay the remaining amounts in smaller chunks than the maximum every time payments are due.
But here's the catch. There's a thing called interest, and what interest does is it makes you pay an extra fee to the credit company. The extra amount you would be paying for is the convenience of not having to pay for your product or service in full right away. The smaller the payments, the more you interest there is accumulated.
There are also different types of credit cards. The differences can be the amount of APR, what each card's benefits are, or some have rewards for spending responsibly.
Is there a limit to how much you can spend?
There actually is. It's based off of something called a credit score. Credit scores determines how likely someone is to pay off their bills on time. The higher the score, the higher the limit.
So as you can see, there is a lot of things to learn about credit. And if used correctly, can help you achieve your goals in life.