I used to have an old one I got from eBay for £230.
P3 600mhz
20gb HD (it came with a 6gb and i put a new one in)
256mb Ram
DVD drive
It worked really well, I could run PS and dreamweaver on it, albeit a little bit slowly. I sold it last May for £250 (with loads of music :P) so I could buy my Mac Mini.
I'm probably going to get a laptop when/if I go to Uni though, much easier to take around with me. Hoipefully I'll get an i/Power/Mac Book if I can afford it