Turtle Rock are going to be extremely generous with Evolve’s DLC. The developer says that all of the DLC maps will be released for free. But wait, there's more! In addition to this, you will also be able to play alongside the DLC characters and monsters that your friends have purchased, so there’ll be no issues between players.
This is a genuinely refreshing approach to gaming and DLC. I'm glad to see player equality becoming a more important business model for game developers.