Right now, Amazon is offering a brand new Lumia 635 for just $39.99 off contract. This version of the phone is meant for AT&T's network.
The Lumia 635 is one of our favorite budget Windows Phone devices. It features a 4.5-inch display, 512MB of RAM, and 8GB of internal storage, which is expandable with a microSD card. The 635 also has a 5MP rear camera capable of shooting 720p video.
As of this writing, there are only six left in stock, so if you want one at this low price, act fast.
Thanks to Michael for the tip!