Valve Software have made the firm's popular multiplayer game Team Fortress 2 free-to-play (F2P), relying on in-game purchases instead of an up front charge.
Originally released in 2007, Team Fortress 2 has been continually enhanced with over 200 updates by developers and Steam-platform overseers Valve.
The F2P announcement comes as part of an "Über Update" release which Valve said was the largest content update for TF2 since it the critically acclaimed 92 per cent Metacritic rated game was first released.
The game is now available to download free for the PC and Mac platforms. Valve is hoping that micro transactions for in-game items will make up for the lack of revenue in selling the game up front.
Hoping to appeal to gamer's desire for customised characters in MMO style take on multiplayer gaming, Valve said: "Tweak your favorite class to suit your gameplay style and personal taste," on the TF2 Steam store page.
Valve's Robin Walker told Develop that the company is not looking to charge ahead with F2P releases of other Valve games.
"With just the data from a single product, it seems dangerous to assume that it would be true for all our products," said Walker.
"Either way, we'll know a heck of a lot more in a couple of months, and that's the kind of thing that gets us excited around the office."