The long-awaited addition of Housing in World of Warcraft is going to cost you. On top of your monthly subscription and the cost of the Midnight expansion itself, some Housing items will require a new in-game currency called “Hearthsteel” that players will have to pay for with real money. World of Warcraft already has hundreds of currencies, and at one point, the game’s main currency, gold, was worth more than the Venezuelan bolivar.