At the end of October 2012, "Krono" was added as an experiment. "Krono" work like the "Plex" currency in "EVE Online": it allows players to buy an in-game item for real money that adds 30 days of Gold subscription to the account. "Krono" can also be traded between players, sold via the Broker or gifted to another player's account. "Krono" is also a much safer way of purchasing game time than purchasing SC cards from players in the game, which may or may not sell you a valid code.