I've tried to keep my costs down as much as possible while still getting decent performance on this gaming rig below...I've purchased EVERYTHING except for the graphics card and my total is about $400.
Im guessing something is going to be on sale, I mean these are popular cards. They definitely are the kind of stuff for like a 1 day sale. I won't expect to save too much tho. Maybe you can get a 7850 for ~150. Looks like they are all about $170 now for the 1gb models.