: Offers digital keys for Windows 8.1 Professional (OEM) at competitive prices, typically around $16.38 .

: Lists Global MS Products Digital Activation Keys for approximately $32.40 .

While mainstream retailers like Best Buy and Amazon have largely transitioned to newer versions, you can still find Windows 8.1 product keys through several specialized software vendors and marketplaces.

: Provides Windows 8.1 Professional OEM keys starting at roughly $21.18 .

: A more traditional vendor that often carries full retail versions or digital license keys, ranging from $82.49 to over $200 for original retail boxes.

: A reliable source for physical "New Old Stock" retail copies, which may include original DVDs and license cards. Prices for full retail media average around $79.99 . Key Identification & Alternatives