There's still one way consumers can upgrade to Windows 10 for free—and Microsoft will shut it down on December 31, even though a majority of the world's PC users still use older versions of Windows.
Microsoft gave Windows 7 and Windows 8.1 users an entire year after the launch of Windows 10 (until July 31, 2016) to upgrade to Windows 10 for free. But there was one exception: those who used assistive technology, such as screen readers, got an indefinite extension.
According to a Microsoft support page, the deadline for those users to upgrade to Windows 10 for free expires by the end of the year, as noted by Slashgear. After that, consumers will have to pay the full price for a Windows license, which costs about $75 from Amazon for a "system builder" license for Windows 10 Home, and more for retail Home or Professional versions.