Nokia Lumia 520 is the best-selling Windows Phone smartphone out there due to its decent specs and affordable price tag. T-Mobile's Lumia 521 is absolutely identical with the international Lumia 520, save for the T-Mobile branding over its front and rear sides.
Walmart is now selling the T-Mobile's Lumia 521 cheaper than ever - just $79.95. No contract is required with the purchase, you just get a pre-paid card but it's up to you if you are going to use it or not.
It's unclear if the offered Nokia Lumia 521 is SIM-locked to T-Mobile or not, so if you aren't a T-Mobile subscriber, you may want do double check on that.
Nokia Lumia 521, just like Lumia 520, is currently running on Windows Phone 8 with Lumia Amber package, but Lumia Black with WP8 GDR3 update is on the way. Microsoft has promised to bring Windows Phone 8.1 to all existing WP8-running smartphones as well.
Christmas is coming in just two weeks, so we guess Lumia 521 might do as a great present.