I have 2 codes from my 2 R9 290's I bought and I'm selling for 0.03 BTC each which is ~25$ USD. Proof:
http://imageshack.com/a/img835/9855/4ar8.jpgBuyer will have to send BTC first unless you have a lot of rep/posts in which case I might consider going first.
For rep my steam profile is
http://steamcommunity.com/id/thetrunk/ and I'm also a seller for tf2shop.net so I will not scam.
First reply, first serve. Send me a PM.