Blizzard RTS community manager Kevyn “Karune” Yu confirms that Battle.net will be free to use.
Yu“when a player buys the StarCraft II box at retail, they will have the ability to play on the new Battle.net for free.”
There has been a lot of speculation whether or not Battle.net, Blizzard’s updated online gaming network, would be a service players would have to pay for. The speculation arose as Blizzard continously have declined answering questions about how Battle.net will be financed.
It seems very likely that Diablo 3 also will be free to play on Battle.net. The question is if they add “microtransactions”, like for wow. Perhaps a player need to pay a few “BlizzPoints” to start a PvP league or tournament.