Right now Walmart has the best price default for the Lumia 521 at $129, but if you go to a a Microsoft store and take the Bing it on challenge, you'll get a $25 discount for orders over $75(which of course covers the 521) making your price $125. I did it this weekend, though the sales guy didn't even make me do the actual bing it on thing, he just scanned a voucher. If you have a Microsoft store around, they seem to have better stocks of the 521 than my local Walmarts.