The currency of the Gods
One Golden Drachma can buy you many things from the gods. One drachma tossed through a rainbow while praying to Iris could net you an Iris Message if she accepts your offering. An Iris Message can allow you to contact someone no matter where they may be. Both parties see the other clear as day, as realistic as though they were speaking face to face, though through a mist.
One drachma is also the cost to buy passage to Hades when you die. The living have been known to buy passage to Hades as well by using many drachma as a bribe.
The Drachma is made of gold and has Zeus’ head stamped on one side, and the empire state building on the other.