From 9to5Toys.com:

As we’ve noted on a few occasions, Sprint pre-paid subsidiaryBoost Mobile is now carrying the iPhone for the first time in its history. Launching today, the iPhone 5s and 5c are $100 off of Apple’s retail price if ordered online. However, Boost is running a special promotion until November 24th where you get an additional $100 off if you switch in store from another carrier. I confirmed the deal with a PR rep who said:

Boost Mobile plans start at $55/month but drop significantly as you make payments on time. Find the nearest Boost Mobile here.