They charge much more than what they have in their account and end up getting screwed. Don't get overexcited with your new power A credit card is a powerful tool if used properly. It is reserved for mature adults who have enough self control to avoid over spending. If you believe you are not ready for a credit card, wait. If you end up overcharging and ruining your credit rating , it will be very difficult to take out a loan for a future purchase.
Many people simply get credit cards to establish a good credit rating by paying their bills on time.
If you would like to take out a large loan on a house or car, then take this option if you are capable of paying on time without overcharging.