Civilization V: Gods & Kings - $3.15 from greenmangaming.com
If you have Civ V you must get on this deal!
Use code: GMG30-DPLIM-DN831
Can activate on Steam.
I believe you can use the code multiple times on other stuff, but just one item, one order per transaction. It's a reputable site. I just went through with the deal and everything went smooth.