If you are near a university, dumpster dive when dorms start to let out. The one I'm at, you can find all sorts of good things that people simply don't want. Computer parts, electronics, furniture. Anything you don't need / want, sell it to a pawn shop or something, and that's additional cash. If you're lucky, you'll find 1/2 to 3/4 of the parts you need.
Just last weekend, I found a laptop in the dumpster near my apartment building. Unfortunately some jackass decided to smash it before tossing it, making it a chore to salvage any of the usable parts, so I just gave up. I've seen other computer stuff in there before though.