Upgrading a computer from 2008 i got for $15. Total cost is just under $100. Built mostly off craigslist.
Started with:
4gb ddr3 corsair xms3 platinum series
EVGA GeForce 9800 GX2
only had the 2 500gb hdds
was in a coolermaster cosmos S case (was too big for where it sits)
Idk what the case is but if you do please tell me. Also this site doesn't have like half the parts in the computer.