Dungeons & Dragons Unlimited is a "free" MMORPG based on D&D 3.5 system. "Free" meaning you don't have to pay anything to play and enjoy the game, but there's a lot of things you can buy for cash* like items or hair styles as well as races, classess and whole areas. In essence it's sorta like playing without having bought an expasion pack. I think. *Instead of cash you can also use "favor points" you can get in game.
What is a DDO VIP? Sounds important, right? Well, it is. DDO VIPs are players who want unlimited access to all of the content DDO has to offer. This newly optional subscription program also allows its gamers to enjoy a number of other exclusive benefits, such as a monthly grant of Turbine Points, priority access to servers, the ability to play all classes and races, additional character slots, a shared bank slot, and much more. The cost of becoming a DDO VIP is only $14.99 per month. So to access all the content there is a monthly fee. Kind of sounds like try before you buy. And also it's a pain to get it to work on OS X. I really don't like companies that don't make their games available and easy to install for windows and OS X users.
As I said, "free". Though from what I've seen most of these things you can actually get for points you get in game, but it's most likely a long grind.