: Provides Windows 8.1 Professional OEM keys starting at roughly $21.18 .
: Lists Global MS Products Digital Activation Keys for approximately $32.40 . where to buy a windows 8.1 product key
Before purchasing a new key, it is worth verifying if you already have one available to you: Find your Windows product key - Microsoft Support : Provides Windows 8
: Offers digital keys for Windows 8.1 Professional (OEM) at competitive prices, typically around $16.38 . typically around $16.38 .