Need recommendations.

Ye Olde Familie Computer is not long for this world. It is old, slow and showing its age more and more often of late.

I recognize there's a rule coined by sci-fi writer David Gerrold applicable to this discussion. It goes something like this:

"Fast. Cheap. Good. Pick two."

Please violate it. If any of you could point me to a reliable source for fast, good and (especially) cheap computers (new or used) I'd be grateful. Remember--I'm just looking for a computer that has to run a scanner/printer/copier, word processing software, and assorted games, with the possibility of upgrading down the line. I don't need speakers, a monitor or printer, either.

Much appreciated!