For reference, I just bought a 2GB Vanilla Nvidia GTX 770 for $100 shipped to Las Vegas, NV. For your model maybe $120-130 shipped.
why_wolf :
I see on ebay one has been bid up to $152 with 4 days left. I suggest watching it and see how high it goes. http://www.ebay.com/itm/gigabyte-gtx770-4gb-oc-rev2-/231685358604?hash=item35f186040c
ebay will get you a higher sell price (sometimes) but once you pay like 10-15% in fees to ebay and paypal its a wash.
I doubt anyone on these forums would pay $150+ for a GTX 770.
On the off chance that you run across a buyer that wants to SLi with another identical model then you may get more money then what I quoted... good luck!