How to trade in your iPhone for cash and cover the cost of the iPhone 4S!

Now that the iPhone 4S has been announced, we figured we'd share how you can get cash for your old model that you can use to put towards the cost of the new one. Did you know that, in most cases, you can get more for your iPhone than what you originally paid for it (if it's a recent model?) The reason is that you likely bought your device with a two-year contract, but when you sell it, the buyer is getting it contract free. For example, Amazon trade-in is offering me $342.50 for my like-new $299 32 GB iPhone 4 that I own. That's enough money to upgrade to a 32 GB iPhone 4S, and is just a little under what I'd need to get a 64 GB model.

Sound good? Here are a few services you can use to trade in your old iPhone (or any other gadgets!):

Gazelle: The easiest of the bunch, they'll even send you a pre-paid label and box to ship your stuff in!
Amazon Trade-in: Offers higher trade-in value than Gazelle, but only pays you in Amazon credit

Of course, there's always eBay and Craigslist, but Gazelle and Amazon are two ways to get quick, guaranteed cash for your old stuff.