StarCraft II will be going Free-To-Play on the 14th of November. Also if you already own Wings of Liberty then you will get Heart of the Swarm for free.
We recognize that you might have found your way here after hearing the news that StarCraft II is going free-to-play very soon—on November 14, to be exact. Curious what that actually means? We know “free-to-play” can mean a lot of things for different games, but we’re here to assure you that when we say that we’re making StarCraft II free-to-play, we really mean it.
Starting November 14, you’ll have free access to the original Wings of Liberty single-player campaign and every Co-op Commander, and will be able to unlock access to StarCraft II’s competitive multiplayer content for free.
More info here.