You should always buy a valid or legit Windows license key. Buy it only from Microsoft or their official partner sites. The keys will work as long as they are not caught. Once Microsoft finds out that the key is not legal, they'll show you a message that you may have purchased an illegal key.
Is it legal to buy product keys?
Warning: You do not buy a Product Key by itself, as they are normally stolen/pirated, Volume Licenses which are not for private use, or MSDN keys which are not to be sold by the original subscription holder. Make sure that you buy the complete sealed package. Read Section: Beware of Product Keys sold separately.
Can I just buy Windows 10 product key?
Windows 10 Home will set you back $139 if you choose to buy a key directly from Microsoft. That's a little on the steep side compared to third-party sellers, who can often be found shipping genuine keys for as little as $25.
Is it legal to buy Windows 10 key online?
It is not legit to buy a cheap Windows 11/10 key from such websites. Microsoft does not endorse it and will file a lawsuit against the people behind such websites if it finds out the websites that sell such keys and bulk deactivate all such leaked keys.
How long does Windows 10 take to activate?
When you run into a problem activating your copy of Windows 10 x (x=Home, Pro, or Business), wait about 30 minutes and try again. If it still won't activate, disconnect the PC from the internet and follow the “activate by phone” instructions.
Is Windows 10 product key free?
If you already have a Windows 7, 8 or 8.1 a software/product key, you can upgrade to Windows 10 for free. You activate it by using the key from one of those older OSes. But note that you can only use a key on a single PC at a time, so if you use that key for a new PC build, any other PC running that key is out of luck.