If you're in the market for a Windows Phone device on AT&T, there are plenty of options, but it's really hard to ignore a metal-framed Nokia Lumia 925 for just $79.99 off contract (or free with a contract, if you don't feel like doing the math on how much you'll save). Granted, that's for a refurbished Lumia 925, but generally they're in like-new condition and sold with a full warranty. $79.99 off contract is a fantastic deal for nearly any phone, let alone one like the Lumia 925 where it retails normally for $399.99.
Hell, this refurbished Lumia 925 matches the price of a Lumia 520 on AT&T's GoPhone prepaid service, while being a notably better device. Not that the Lumia 520 is a bad device — the Lumia 925 is just a better one. For budget conscious shoppers, it's hard to beat a better smartphone for the same price.
Of course, you could always go to the other end of the Windows Phone price spectrum and buy a Nokia Lumia 1520 from AT&T for $199.99. That's with a contract; off-contract pricing rings in at $584.99. Which still isn't bad for such an enormous flagship device.