How much can/should I sell my PC for?

[Conman12314]

I have a gaming PC, custom built, and I am wondering how much I could sell it for.

GPU: EVGA GeForce GTX 960 4GB SSC GAMING ACX 2.0+
CPU: Intel Core 2 Quard Q9300 @ 2.5ghz
MOBO: Gateway G33M05G1, Intel
RAM: 6GB DDR2
HDD: 1 TB (Can't find brand, sorry.)\\
PSU: 550 W G Series
Case: Gateway FX, Orange and Black.

USD in answers, please, and thanks for help.

 

[Brodwell]

I would say $300-400 ish. 775 is a old platform.