<< As Russ said, you could use a debit card, but try to find one that has some fraud protection. Through Bank of America, I have their "gold" debit card which offers, I believe, $500 in fraud protection for online purchases. No other local banks do that (I don't believe). >>
I got one of those. They're cool, and yet they suck. I spend thousands, and yet I'm not building my credit for the future. Looks like I"M heading to my bank to day to get a real credit card.