How to exchange my old iPhone for an iPhone 5?

How do I exchange my old iPhone for an iPhone 5?

Extend your contract 2 years and the carrier will pick up most of the cost.
You can recycle old phones on apple's site and they will give you store credit for doing that:
http://www.apple.com/...recycling/

If you are willing to sll your old iphone, Then I will suggest you to sell it on ebay.com, you will definitely get Best deal. And after with those money which you'll get after deal, you may buy an iphone 5.

I'm lucky to exchange my iPhone 3g for iPhone 5 using the site below. Maybe you can try.