Do you need the monitor, keyboard, mouse and os?
if yes to all these things. $1400ish to max it at around 1080p @ 60 fps
If you don't need all these things, around $ $1100 or less (depending on the case)
Basic build
3570k
CM 212 EVO
8GB DDR3 1600 mhz ram
GTX 670
A good quality 500w PSU