I have a lot of buddies who seem to use Credit cards as if they were cash. They spend money they don't have and when they hit their limit just open another card up.
People don't realize how much money they are losing by having to pay 10-25% APR's on Credit cards. Instead of spending money you don't have, only spend what you can afford to pay for each month. Credit card interest is compounded monthly thus a 20% APR is really much m ore if you don't pay it off each month.
If used properly one can actually make money by using credit cards. There are several companies offering 1-2% cash back on each and every purchase you make. If you get a card and instead of just paying the min balance due each month you instead pay it off in full each and every month you will build up your credit score while also getting back 1-2% in cash each month.
Be smart. Plan things out, and understand how much money you will lose if you don't pay the account off in full each month. Those who don;t are the ones who are digging a whole for themselves for decades to come.
Matt