U.S. customers interested in a cheap Windows Phone device can now purchase the Nokia Lumia 520 and Lumia 521 at significant discounts from the Microsoft Store.

The Lumia 520 and Lumia 521 have seen huge success due to their affordable price tags, although they are by no means high-end smartphones. These devices aim to cater to the low-end segment of the market and they've never been more affordable.

The U.S. Microsoft Store is now offering the Nokia Lumia 520 and Lumia 521 for $40 and $30 discounts, respectively, on a no-contract deal. Although the devices are not on contract, however, they are still tied to carriers. The Nokia Lumia 520 will still feature AT&T's radios, while the Lumia 521 comes with T-Mobile branding.

The AT&T Nokia Lumia 520 now costs just $59 instead of the previous $99 price tag, while the slightly superior T-Mobile Nokia Lumia 521 drops its price from $99 to $69. These offers will be available until Jan. 12, or while supplies last.

The Nokia Lumia 1520 made its debut back in April 2013 as an entry-level smartphone running Microsoft's Windows Phone 8 OS. The handset packs a Qualcomm S4 processor clocked at 1GHz, Adreno 305 graphics, and 512MB of RAM. Other specs include a 4-inch WVGA display, meaning a modest resolution of 800 x 480 pixels.

Other specs include a 5-megapixel rear camera with 4x zoom and 28mm focal length, 8GB of internal storage capacity, and a microSD card slot for additional memory of up to 64GB.

The Nokia Lumia 521, meanwhile, is a slightly enhanced version of the Lumia 520, sporting virtually the same specs but bringing 4G to the table. This model is exclusive to T-Mobile in the U.S.

The discounts are available only from the U.S. Microsoft Store and the promotion will only last for a limited time, until Jan. 15. Head here to get the Nokia Lumia 520 for just $59 without a contract, or here to get the $69 Nokia Lumia 521. They may not be high-end smartphones, but they do come with more than decent specifications for these low price tags.