Factorio. The most value for money i have gotten out of any game. Even more so then free games... the replayabillity is insane. Even before you add mods and multiplayer. I have 1500 hours just on the latest map..
Rimworld. When you need to rage quick factorio for a month, you sell the organs of your enemies for drugs. And you make clothes out of their skin. Hopefully in that order..