The big thing with credit cards is that if you get one without annual fees and pay off your balance on time every month, you're fine. If you pay only the minimum or close to it, you will pay lots in interest (it's how they make money). If you pay late, they ding you with fees. But if you get a card with no annual fee (a fee for having the card, basically) and pay it off in full and on time every time you use it, then you get the benefits of having a credit card with no extra expense.

Me, I use my credit card for everything, because I do/can pay it off in full every month and I get "reward points" for using my card which I can use to do things like get cash back or buy mp3s and such. As long as you don't fall into the trap of thinking "It doesn't matter if I don't have the money now, I'll just put it on the card and pay later!" you'll probably be fine.