I've used credit cards all throughout my college years. They have been wonderful! Spectacular even! I've probably earned close to one thousand dollars in rewards and not spent a penny in interest fees. As long as you get a credit card that gives you 2-5% cash back, you're basically going to get paid for the money you'd spend anyway. Now this is where it is easy to get carried away and justify spending money that you don't have in the bank. The best way to use this hunk of plastic is to pretend it's just a debit card on a month long delay. Make sure that you can pay off the total amount at the end of the month and you'll be on track to get your rewards without those pesky interest fees.
Ok, ok, I have to confess that I don't always follow my advice to the letter. When money gets extremely tight I have been known to put purchases on credit cards without having that money in the bank. I don't recommend this! AND the only way I ever do this is when I can get a promotional offer for 0% interest over the course of a 1 or 2 year period. It is risky business, but it at least gives a cushion of time to pay off that account without paying any interest whatsoever.
So be smart. If you know that you can be a responsible spender and want to get a discount on all the everyday stuff you buy. I do recommend getting a credit card. However, if you know that you get carried away easily, then try to stick to cash or debit cards (at least until you find that you can handle a credit card.)