If you are the type of person who doesn't feel the need to buy the latest and greatest device, swappa is the place to go. They do a really good job vetting both their sellers and their merchandise, and you can buy with confidence. When something goes wrong with a sale, the swappa staff is there for you and are very responsive. Much better than dealing with the wild west that is ebay :) And their prices are often better than what I find on other sites.