Not everyone in the US can get a credit card. Everyone can get a debit card, though, as long as they have a bank account. There is a big difference. A debit card looks just like a credit card, but it deducts the actual price directly from your bank account. If you don't have enough money in your account, you get declined. A credit card, depending on what kind it is and how good your credit score is (meaning, how dependable you are in paying your bills on time), covers the price of your purchase, but adds the cost to your credit. Each month, you have to pay it off and some even add on high interest rates. If you don't pay your card on time, they can reposess you and it ruins your credit for a very long time.
In dramas, they use the credit cards to show off a character's wealth. It's always the chaebols who use them extravagantly because they have the money to pay it off. The ones who are shown having their card declined at the ATM, though? Those are the poorer characters with a debit card. :p
