On Japanese TV, you may notice that a lot of commercials for smartphone social games emphasize the word muryō (free). Consumers have been purchasing digital content on their phones for years, even since the clam-shell cellphone days. Now, more and more Japanese people are migrating to the sort of smartphones that are popular around the world, and Japan’s smartphone app business has overtaken the United States to become the world’s largest. Believe it or not, this is largely down to players of free social games who purchase virtual items within the game.

And now, publishers are trying to replicate this formula with microtransactions in non-game apps, too.

In the most popular social games, over 90 percent of users never pay anything. While this majority of players get to enjoy the game for free, they also play a role in making the action more interesting for paid players, since social games involve some level of interaction with other players online.

For a few hundred yen each time, users can choose to buy items that give them an advantage or special privileges. They may only make up a small percentage of the overall user base, but their desire to beat the casual players and be seen as elite is enough to generate huge profits for the games’ publishers, especially as offering a game ostensibly for free means the user base itself can be in the millions.

This “basically free” model is now being tested in several non-game apps, hoping to exploit consumers who are willing spend on in-app purchases.