I need to buy a second CD Key for Warband, and since I already have one copy of the game I was wondering if there is a trust worthy website from where I can just buy a key?

I did some searching and found these two websites;

http://www.cdkeyhouse.com/
http://www.cdkeyexpress.com/

Problem is I couldn't find any conclusive reviews about either of them.

So if anyone here knows some other website, or knows something about these two websites, I'll be really grateful if they can help me.