The Apple iPhone BuyBack Program is now available in Apple retail stores and customers who are under contract can get up to $280 for their old iPhone, if they are planning on purchasing a new one. To take advantage of this program, you just have to take your iPhone to your local Apple Store. A representative will then work with you to determine the value of your iPhone and help you choose a new one.
The iPhone must be able to turn on and the value you can get depends on the shape of your iPhone including the screen, if there has been any liquid damages and how the buttons operate. If you want to find another buyback program, you can check with Radio Shack, Best Buy, Nextworth or Target. If you are hoping to get the most amount of money back from your iPhone however, you might want to just try to sell it outright. You can do this by placing it for sale at eBay or Craigslist.