An i810 motherboard from the tekram online store (
The S381-M is $35),
A celeron less then 600Mhz ($65) (must be less or won't work in motherboard)
64Mb of cheap ram ($25),
Cheap case w/ 230-250W powersupply ($24-50),
G-orb ($10),
Hard drives are hard to get good deals on, try for a coupon special or something ($90),
CD-Rom get a decent one, no one like crappy lound cd-roms ($35)
Keyboard logitech standard ($11) or splurge with an Itouch for $16
Mouse logitech 1st wheel mouse ($14)
Crap speakers ($10-15)
Then you are up to $320-360 spend the rest on monitor, or use old monitor.