The metro stations in Sao Paulo have book vending machines. The collection of books ranges from history, political philosophy, cooking, government, self-help, and children’s stories (click for a close-up of titles). The machine has a banner that says: “Pay whatever you think it is worth”. The only caveat is that you cannot use coins, only notes, so each book is minimally a dollar — which still seems like a deal. From hanging around this machine on two separate occasions, I noticed that it’s popular among people of all stripes and ages.