https://techcrunch.com/2017/10/19/facebook-messenger-game-ads-in-app-purchases/

Facebook is finally giving developers a reason to build games for Messenger while also opening a new revenue stream for the chat app. After launching HTML5 ‘Instant Games’ inside Messenger like Pac-Man, Space Invaders, and Words With Friends Frenzy in November 2016, today Facebook is allowing developers to add in-app purchases as well as interstitial and rewarded video ads. Players get a virtual good or bonus life in exchange for watching rewarded videos.

Facebook will take a cut of the ads shown in Messenger games that are routed from its Facebook Audience Network, and will begin appearing in some games on iOS and Android. In-app purchases will only start testing on Android, with Google Play taking its standard 30% cut. Developers who want access to the monetization beta program can sign up here, while advertisers who don’t want their Audience Network ads from appearing in games can opt out.