I saw some pretty decent trade-in prices for iPhones as credit from Amazon.com. The quoted prices you get lock in even after the anticipated iPhone 6 announcment in less than a week from now.

So if you think there is a chance you will want to upgrade, its best you lock in the trade-in price now and decide later. No obligation to trade-in / sell if you change your mind.

Update on 2014-09-13 19:57 by Mike Mu

Amazon is offering up to a $400 Amazon credit when you trade in a qualifying Apple product. Includes iPhones, iPads, iPods and more. Click the "Trade in" button under the item you have to select condition and see what kind of credit you can get for it.

They are offering up to $276 for the iPhone 5s (16GB), up to $400 for the iPhone 5s (64GB), up to $104 for the iPhone 4s (16GB) and up to $250 for the iPhone 5 (16GB).