Some suggestions to add
bedeals (actually I don't really trust this site, the ssl is untrusted lately and the "deals" are pretty much what things go for on amazon)
I also check giveawayoftheday.com, but they have maybe one good thing a year, and it's not something you can do from your phone.
Current Device: Lumia 820.
Previous Device: Titan I
HD2 and a number of other WM6 devices.