I paid full price for it on release. Now they are making money with the 2nd and 3rd part of the campaign (sadly, both inferior), and also probably from the coop commanders DLCs.
(Most players never touch competitive multiplayer, but quite a lot might try playing with friends vs the AI ?)
Thank you for clarifying, yes I should have mentioned that the multiplayer / vs AI is free, but there's paid content as well (single player campaigns, unit/building skins, etc).
To me the writing of the Single Player campaigns was grating ("bout time we kick this revolution into overdrive", rawr!) but the gameplay was good, so no hard complains. I liked the unit variety on the Protoss and Zerg campaigns compared to the WoL "buy upgrades and mercenaries" approach.
(Most players never touch competitive multiplayer, but quite a lot might try playing with friends vs the AI ?)