The mobile versions of Sonic & All-Stars Racing Transformed have gone free-to-play. Sega announced that both the iOS and Android versions are now available to download for free, and more content is coming later this month.
Next Tuesday, April 29, they'll get Wreck-It Ralph and Metal Sonic as unlockable characters. It will also add a World Tour Chapter and Boss Cup Grand Prix modes, along with two more tracks: OutRun Bay and Galactic Parade. The update will allow players to record their races and share them on social networks for bragging rights as well. Presumably, since the game has gone F2P, extras like racers and tracks will be paid content.