Yea, i bought it today for that price on Steam. I go to play it and it asks me for my serial # (not product key, mind you), and it is not the correct number combination of letters and numbers to make it a correct serial #. So (a) it will not let me register the game properly, and ( get into the game to play it at all. Bummer. I should send this complaint into Stardock technical support for them to rectify it. Kneebender 

Well that's really bad luck, I activated mine today just fine.  I actually know of someone on the Steam forums who similarly couldn't get it to work. :/

Replied.

Please let me know if this does not resolve the issue.