At the end of 2016, Microsoft sold out of all of its Lumias in its online Store. Many of them reappeared a week later, and the company has kept a decent stock since. Well, they're all gone now, as while the listings for four phones remain, they're all out of stock.
During the firm's earnings call for the third quarter of its fiscal year (the first quarter of the calendar year), Microsoft said that it made just $5 million in revenue from phone hardware, and that it should finally be done selling first-party phones by the end of the fiscal year, which means by the end of this month. With this in mind, it might be safe to assume that the company won't be restocking any of its handsets.
As it stands, there are only two carriers left that sell Windows phones. Cricket Wireless still sells the refurbished Lumia 640 for $0.99 (with activation), and Verizon is still offering the Lumia 735 for $120.
Microsoft isn't done with Windows 10 on phones just yet though. Earlier today, we got a look at CShell running on an HP Elite x3. CShell will adapt the interface between different devices and form factors, including phones.