There are many reasons why they do this, not least of which is that they handle Steam keys, and by imposing a minimum cost, it means bad actors can't as easily

There are many reasons why they do this, not least of which is that they handle Steam keys, and by imposing a minimum cost, it means bad actors can't as easily get tonnes of Steam keys for resale or using their purchases to game Steam and other services in other ways. They now apply this policy across the board. Read more here: http://www.gamesradar.com/humble-indie-bundle-responds-steam-key-exploiters-1-minimum/ http://www.gamesradar.com/humble-indie-bundle-responds-steam...