How can I tell if a Windows Key is legit?

[exHorizon]

I found some rather inexpensive Windows 8.1 keys on Ebay for about $30, but I have no idea how to tell if they are legitimate or not?

http://www.ebay.com/itm/Windows-8-1...975261?hash=item3d1194e35d:g:DbsAAOSwUuFWvkkr

 

[exHorizon]

If they come with a CoA, they are legit. If not, they aren't and go against the ToS for Windows.

A what? And how do I check if it comes with a "CoA"?

 

[unksol]

If it's on eBay for $30 it's not legit. End of story.

It cost $80-$100 minimum. Buy it from an actual retailer like Amazon or newegg or you will get a fake.

 

[ThatVietGuy]

The last time I bought a key that cheap on eBay I got an email from eBay saying to not pay the seller and that the seller got shut down.

That should tell you a lot.