Despite having been out for roughly six months, the HTC One X is still one of the best smartphones you can buy on AT&T. The design and build quality are both fantastic, Sense is tolerable, and it works on AT&T's blazing fast LTE network.
If you walk into an AT&T store right now to buy this phone, you'll be leaving $100 lighter. If, however, you want to grab this phone without spending more than a penny, Amazon Wireless can make that happen. This, of course, requires you to sign a two-year agreement, but the good news is that this deal is for both new contracts and upgrades.