17.4
Google AdMob is a free platform for earning revenue from mobile app advertising.
Free planAndroidiOSWeb
Google AdMob is a free platform for earning revenue from mobile app advertising.
DT FairBid is a free publisher monetization service for integrating and managing multiple ad networks on apps or other publisher properties.

AppLovin MAX is a monetization platform that helps mobile games earn revenue from ad impressions.
Chartboost Mediation is a free monetization solution for mobile app developers on Android and iOS.