The Nokia Lumia 521 is now on sale for $79.95 from Amazon and Walmart. That is the complete non-contract price which makes the phone a great idea for a holiday gift. Amazon only has a limited number in stock, so keep that in mind when deciding when and where to order from.
The Nokia Lumia 520/521 will soon be replaced on the low-end of the Lumia totem pole by the Nokia Lumia 525 which replaces the 512MB of RAM on the Lumia 520 with 1GB of RAM, while most of the other specs remain the same.
source: Walmart, Amazon via WMPoweruser