[Dan in PA]

Hmm...I'm assuming you're not talking point and shoot, right? You can get a D3000 with lens for $450 on Amazon, I'd say that'd be a good place to start. I'd recommend doing research on the lenses/flashes/whatever available for brands ofDSLRs in your price range since you may wish to upgrade in the future. When you buy a DSLR, you're really buying into a system and not just the camera itself. In my humble opinion, you can't go wrong with a Canon or a Nikon, it's a personal choice based on ergonomics and individual features/ price.

EDIT: I'm an idiot, I read the used price :-/