You can get it now and keep forever.
Humble Bundle is the one of the most popular website in the gaming industry. It is creating great bundles with expensive games and selling them with a fixed price. And sometimes they are giving free games. And today it is giving Lego The Hobbit for free.
Lego The Hobbit is free in Humble Bundle today. You only need to add it to your Humble Bundle account. After that you will have game key and you can activate it. Don't forget that the game will be free until December 15, 2019 at 10AM PT. And you need to activate the key on Steam before December 20 at 10AM PT.
If you like LEGO games or Lord of the Rings' games, you can get this game for free. And you can join to Bilbo Baggins and his dwarves friends in their adventure and even kill LEGO Smaug. You can get the game from here.