The venerable Guild Wars franchise is one of the most loved MMORPGs to feature no subscription fees. Users simply purchase the game and are free to roam, at no charge, the Guild Wars universe. The franchise recently welcomed the news that software sales worldwide had passed 2 million units.
It would seem that people both enjoy the excellent balance and gameplay of Guild Wars along with the no-recurring fees. With a Level 20 cap and a much bigger focus on skill, Guild Wars almost eliminates the concept of cheaters and gold farmers. There is now also two huge worlds to explore, with an impressive third coming somewhere down the road.
As a comparison, World of Warcraft, the most popular (by far) MMO on the market has 6.5 million subscribers.