Just like with GOG and Full Throttle Remastered earlier today, LEGO The Hobbit is available for free on Humble Bundle, but you need to be subscribed to their newsletter in order to get the game. Once you are, just click on its link in the home page, and they'll give a Steam key for you to redeem it.
This offer expires on Saturday, so you better hurry.
https://www.humblebundle.com/