It is DreamSpark or MSDN key for Development to test their apps. When you want to buy something in windows store, you may can not change the key's country. That is why it very cheap.
MSDN Licensing
http://msdn.microsoft.com/en-us/subscriptions/cc150618.aspx
And do not use this key in your company because you may be fined due to the terms of use.
Is this with function equal to when you buy Win 8 from regular shops?
I am interested but need more detail.
FYI, for those interested:
http://www.steamtrades.com/trade/35Gpc/h-windows-7-8-81-pro-w-tf2-keys
Different Trader, but same comments apply.\
EDIT:
Just so you know, Windows keys being offered at ridiculously low prices are more than likely from MSDN/Dreamspark accounts. It is against the ToS to do what is being done here.
Microsoft, at any point, could revoke the legitimacy of these keys because they are NOT legitimate... IF they are from MSDN/Dreamspark.
MSDN/Dreamspark is meant for educational and testing purposes and only for the person they are issues to.
They are not meant to be profited from in any way.
TL;DR:
Accept Windows keys at your own risk, Microsoft hates when people take advantage of their (awesome) programs for testing. They could disable them at any point.
Yup, this is piracy
http://www.microsoft.com/oem/en/licensing/antipiracy/Pages/COA_hologram.aspx#fbid=0QnsBVNqcwj
Windows 7 Pro Multilang key - 8 keys
Windows 8 Pro Multilang key ( free update to 8.1 ) - 10 keys (out of stock now)
Windows 8.1 Pro Multilang key - 12 keys (out of stock now)
only keys no other offers thanks
you can add me but leave a reply here first please