I might have an 800MHz Athalon to sell, cheap.

More generally, look for bargains. Not just the "half price" computer junk stores, but more to the source—anyone getting rid of stuff, upgrading, etc.? Even aquantances you are not as close to might barter, where you help them with the upgrade if you keep the replaced part.

I maintained my PC "on the cheap" for many years, before I got a career.