Right when I bought two copies at Best Buy, I find this on their news board. I think you need to purchase this game from their website, retailers don't count. But either way, if you're looking to get your friends into a game, it's normally $40 per copy. Save $20 on a second.
http://forums.demigodthegame.com/350280
http://forums.demigodthegame.com/350280