As noted in Chapter 1, Experiencing the OUYA, the OUYA console was built around a free-to-try model that every game uploaded to the marketplace must adhere to. This means that your game must function at some level without the player having to purchase anything, which lets them determine whether they enjoy the game without having to purchase it based solely on the marketplace page. If the player enjoys the demo, they can unlock the game's full functionality by purchasing it from within the game.

The following is a screenshot of the game MirrorMoon EP, which features an option to unlock the full game from the pause menu:

Not all games have in-app purchasing in them, but a majority of those that do feature the "full game unlock" purchase option. One-time purchases such as a full game unlock are called entitlements.