Microsoft's Lumia BOGO (buy-one-get-one) deal has officially started in the U.S. and Canada, and the company is offering a free Lumia 950 when a customer purchases an unlocked version of Lumia 950 XL smartphone.

PCWorld reported that the Redmond-based tech giant is having issues with the dwindling sales of its Windows phone and giving units away is one way to lessen the stocks.

It was also recently reported that overall, the company has sold barely 2.3 million units of Lumia phones during the first quarter of the year, compared to 8.6 million a year ago.

The deal is pretty much straightforward and nothing fancy is involved. Interested customers can directly purchase the Lumia 950 XL from the Microsoft Store for US$649, and is eligible to receive the free Lumia 950 in black color. One will be saving US$549, the value of the free Lumia phone. Both phones will be an unlocked version, which means that it will work on majority of the carriers within the two countries.

The Microsoft Lumia 950 XL has a 5.7-inch WQHD AMOLED display that offers a 2560 x 1440 pixel screen resolution with 518 ppi pixel density, and protected by Corning Gorilla Glass 4. It is powered by an octa-core Qualcomm Snapdragon 810 paired with 3 GB of RAM. A 32 GB built-in storage is also included, expandable up to 200 GB via a compatible microSD card. An additional cloud storage is available via the company's OneDrive.

The smartphone also has a 20 MP main camera with ZEISS' 6-lens optics, that features auto focus and a two-stage capture key. It also offers a 2X digital zoom and optical image stabilization (OIS). It can take 4K videos @ 30 fps. The front camera is a 5 MP wide angle lens that works superbly during video call and video recording. The front snapper is capable of capturing 1080p videos.

The Microsoft Lumia 950 on the other hand, is a 5.2-inch AMOLED display smartphone that offers a 1440 x 2560 pixel screen resolution with 564 ppi pixel density. It is powered by a less powerful processor, a hexa-core Snapdragon 808, 3 GB of RAM and 32 GB internal memory. The rest of the specs are the same with its bigger brother.

The Lumia BOGO deal will run until May or until supplies last.