How much for my used r9 270x

I just took a peek at Craigslist and saw a couple of those same cards listed for $140-150. If you really want to sell an item... the best thing is to first check out the selling prices in your area and undercut the prices listed to stand out... so you could ask for $150... but I would consider listing it for $125-130... include lots of photos.. and advertise whether or not you have the original box.. and if so, display a photo of that as well.
 
I just upgraded my gpu's. I had 2 x XFX Radeon R9 270 X's with 4gb GDDR5 each with original boxes for warranty. (as to your 2Gb GDDR5 cards) I sold mine for $200 for the pair. Not to a friend, just a guy where I get job supplies. I paid $225.00 per card at BestBuy. Each card came with 4 free steam games. which I kept when I sold the cards. which if you received any free games you should take that into count.