Buy a used A-Bit motherboard, a used 566 celeron processor and over clock it
to 850 Mhz. Might have 50 bucks in that. Then buy some used 256mg PC100 memory for about 10 bucks. and a older 32mb invida video card for about 25
bucks. You will have less than 100 bucks in it. Use it for a year and sell it for
$100 When a 300Mhz was the fastest CPU I overclocked mine to 527mhz
Now I just buy dell's there cheap.

 

Another GREAT store although Newegg beats there price whenever I make a large order.

I also build/repair computers and I would chime in more but it seems everyone else has a good handle on things.

 

They both have goob prices, Mwave has a better return policy, no restocking charge. And never had any problem with replacing defective parts. Just stay away from Tigerdirect.