My latest build :
I got an EVGA 750i mobo + Pentium D 925 CPU + 9800GT video card for $45 off ebay ( free shipping )
Added a 5850 today and sold the 9800GT that came w\ the mobo for 45. So my mobo and cpu were free, $30 for a new psu, 80 for the 5770, and 170 for the 5850. had the ram and hdd in my garage.
it's getting 190MH on the 5770 and 290MH on the 5850. So 480MH build for $280.