The just released and Papers Please-like The Westport Independent has gone free on Amazon Underground. It seems to be only available in the US for now.
Amazon Underground is a service that lets player choose from a number of games that are totally free and that pays developers $0.002 per minute played.
You can get it here.
We called The Westport Independent "A thoughtful examination of press censorship and its repercussions" and we gave it 7/10.