After waisting untold hours posting to craigslist, waiting for responses and getting stood up in coffee shops selling my iPhone every time a new one comes out, I gotta say I couldn't be happier selling my iPhone 6 to Apple for $350 to buy the iPhone 6S. In and out in a couple of minutes with a fixed price. Those saved hours are now much more valuable to me than squeezing an extra $100 profit out.