[PC, Steam] Free: Infected Shelter @ Steam

Infected Shelter is now free according to Steam DB price history

Infected Shelter is an ultra-violent rogue-lite post-apocalyptic brawler. Singleplayer and co-op for up to four players.

Every run is different because of the randomly generated content. Players can loot more than 170 different blueprints of permanent improvements and this is the key to Infected Shelter's replayability. Instead of just collecting loot to make yourself more powerful during a single run, you unlock new weapons, clothes, skills, relics and RPG-like character improvements that change how you play the game in the following runs.

via Scrooge McDeal at OzBargain