The Super Hero MMO, DC Universe Online, has gone free to play as of November 1st

As stated in a press release a coule of months ago:

There will be three levels of access:

Free: New players will now have access to the current gameplay in DC Universe Online (including Gotham City, Metropolis, and all current raids and alerts), with the ability to create two characters, join a league and many other benefits. Free level players will be able to purchase downloadable game packs/updates, additional character slots, powers and more through microtransactions.

Premium: Any player who has spent at least $5 USD (including former paid subscribers and new players who have purchased $5 of in-game items) will qualify for the Premium access level. Premium level players will have more benefits available to them than the Free level player, including additional character slots, additional inventory slots, and higher cash limits. Downloadable adventure packs, additional character slots, and more can be purchased in-game.

Legendary: Maximum features and benefits are included at this level. Loaded with enhanced additional features, Legendary access will be available for a $14.99 USD monthly fee and includes all DLC packs at no cost, more than 15 character slots, more than 80 inventory slots, the ability to form unrestricted-sized leagues, and many other benefits.

More information on the DCUO free-to-play access levels can be found here: dcuniverseonline.com/free.