The Battlefield series of action games is expanding its horizons with another free to play entry in the form of Battlefield: Play4Free for PCs early in the new year.

Boasting 32-player online matches, the plan is to fund the free experience with optional paid-for extras: cosmetic tweaks, weapons, even early access into Battlefield 3 are on the cards.

It joins versions of Need for Speed, FIFA, Tiger Woods golf, and its cartoon-styled predecessor, Battlefield: Heroes.

The free-to-play model certainly isn't new, but is most common in role-playing adventures ( Allods Online, Lord of the Rings Online, Maple Story, Free Realms), though others are now joining.

Age of Empires Online is an empire-building strategy game; League of Legends is inspired by a custom map from Warcraft III; WarRock is one of the more well-known action games.

Though there's not yet a launch date more precise than "Spring 2011" (March to May), there is a Battlefield Play4Free testing phase that will start at the end of November - willing participants can sign up at the website.