Blizzard has finally made Diablo III starter edition free for everybody to play.
The Starter Edition allows you to fight your way up to the Skeleton King boss in Act I, and advance all the way to level 13, without having to purchase a copy of Diablo III.
Existing Battle.net users can sign up for the Diablo III Starter Edition through the "Your Game Accounts" section. New Battle.net users will have the starter edition license added to their accounts automatically upon registration.
Certain game features are restricted on Starter Edition accounts; however, any progress and achievements earned while playing the Starter Edition will automatically carry over if the player decides to upgrade to the full version of Diablo III.