StarCraft 2 is "almost" free to play but almost no one knows about that. You should download Starter Edition and You will be able to play! Of course You will not receive the full content of Campaign or Multi but You can always play vs AI, try some mods, arcade games etc. Believe me, it's worth trying! And yes, SE includes Legacy of the Void units and maps....what are You waiting for?! Go, create account at Battle.net and You will be able to download Starter Edition of StarCraft 2 !!
Europe:
https://eu.battle.net/account/en/creation/tos.html?country=GBR
America:
https://us.battle.net/account/en/creation/tos.html?country=USA
GL & HF !! :)