In the early days, gamers had to mostly pay for Massively Multiplayer Online Role Playing Games (MMORPG). But today some of the most popular MMO's are becoming free to compete with industry giant World of Warcraft.

Whether you want to be a superhero defending the innocent or a fantasy warrior slaying dragons, players will fine a variety of online options without paying a dime.

But these games do feature a catch, and developers have found a way to make money. Most of these games fall into the freemium Internet business model, giving players free content to play and lots of VIP features for players who are willing to cough up the extra cash.

Here is a list of the best free-to-play MMO's on the marketplace and the catches developers use to get players to pay for premium content.

City of Heroes Freedom
City of Heroes: Freedom NCsoft
Lord of The Rings Online
Lord of The Rings Online Tech Digest
World of Warcraft
World of Warcraft Blizzard
Guild Wars
Guild Wars NCSOFT
DC Universe Online
DC Universe Online WB Games
Age of Conan Unchained
Age of Conan: Unchained Funcom
Everquest II Extended
Everquest II: Extended Sony Online Entertainment
Champions Online Free for All
Champions Online: Free for All Games Radar
Perfect World
Perfect World Perfect World Entertainment
DD Online Unlimited
D&D Online: Unlimited Turbine
Free