well 4 gigs of ram is 30 ah the hdd is about 50-80, A gtx 460 is 160. odds are its an i5 from the previous generation. But it's a decent buy IF those graphics cards are not the SE edition.
It's probably cheaper than you could build yourself but barly rough estimate on what it would cost to do this yourself
new i5+mobo min 300 (unless you are near a microcenter.)
gpus min 300
psu min 75
so to build a simular but newer (and better) computer yourself you would be looking at 925 ish.