Now through April 21st, any AT&T customer who purchases a Lumia 900 will receive a $100 rebate from Nokia -- effectively making the device free. Ostensibly a gesture of goodwill from the Finnish manufacturer, which confirmed that a small number of early handsets shipped with faulty software that caused memory management issues and eventually data connectivity woes. It insists this problem is now fixed, and that come April 16th, all affected consumers may swap their device at any AT&T store or merely download the update. Previously, AT&T had announced a $100 mail-in rebate for new subscribers that'd purchased the Lumia 900, but thanks to Nokia, it's now effectively free for all. You might wanna jump on this one.
Update: To clear up any confusion on the rebate process, Nokia states, "Every individual who has already purchased a Nokia Lumia 900 - or who will purchase one between now and April 21st – will receive a $100 credit to their AT&T bill from Nokia." Hope this helps!