Intel 3570K $190
AsRock Z77 Pro4 LGA 1155 ATX $79
8 gig mem $50
GT550 Ti video $120
500GB Black Caviar HD $80
This should keep you Happy for a couple of years....
But then you need an operating system for 80-100 $
A case anywhere from 30-100 $
an ssd is way better than most hard drives for the same price almost now.
then you will need a monitor for 100 $