I have recently learn about a new economic system called BITCOIN, it is a peer-to-peer currency. Peer-to-peer means that no central authority issues new money or tracks transactions. These tasks are managed collectively by the network. http://www.bitcoin.org/.
I think that this sould be acceptep as a alternative way of buying energy and weapons or player to player transaction
Speaking of bitcoins, there's this bitcoin casino game called dragons tale, it's really unique, you get bitmills from herbs and soldiers, that's when you can make your first bet. I have my avatar set a businessman and I like to gamble in it, it's a pretty fun game, even when you lose you can always get back on your feet with soldiers and herbs and sometimes even other players.
http://www.dragons.tl/