Microsoft' been struggling so far this year trying to bump the sales of Windows Phone so it comes as no surprise that business partner Nokia is aggressively pushing its Lumia-badged line of Windows Phone, especially Lumia 521, at dirt-cheap prices.

If you missed buying Nokia Lumia 521, which sold out during a run on HSN recently, don't sweat. The T-Mobile exclusive will hit Walmart and Microsoft stores next week for only $150 off-contract. It means that though Lumia 521 will come bundled with a T-Mobile plan, the buyer has the option to leave T-Mobile at any point.

Granted, Lumia 521 isn't a top-end smartphone and it doesn't pretend to be one, either - it sports a 4-inch 800x480 pixel display, is powered by a dual-core 1GHz processor and packs a no-frills 5-megapixel rear-facing shooter, 512MB RAM and 8GB internal storage (fortunately, it also has a microSD card slot). However, what's attractive about Nokia Lumia 521 is that this Windows Phone 8 devie is dirt cheap and it's a good buy for price-conscious smartphone shoppers, who're looking for alternatives to the subsidized iPhones and Android devices that come with 2-year service contract.

Recently, Nokia's top boss Stephen Elop remarked that Windows Phone devices need to be sold at low price points if Microsoft's mobile operating system is to compete effectively against the Android. "There's definitely an opportunity to push to even lower price points," Elop said. Going by Elop's words, Lumia 521, if it strikes gold, could be the WMD that Microsoft and Nokia are looking to unleash on their rivals.

Meanwhile, it's only fair to warn first-time smartphone shoppers that Lumia 521 is a good device but it'll come only in white color (at least for quite some time) and you'll suffer from the "app gap" syndrome till you decide to switch the mobile OS or Microsoft gets its acts together (whichever happens first).