Depending on the business model of your game, there are many potential revenue sources for your game.

Paid Games: A pay gate where the user is required to spend in order to consume your content. This model limits your revenue cap in that the expected outcome is the user will not be charged for additional in-app purchases (unless DLC is used) or burdened by in game advertising.

Freemium (Free-to-Play): A free to download game where users are invited to grind or pay. In game virtual currencies are common in these types of games. These currencies can be rewarded, purchased, received for gameplay, incentivized against advertising, and eventually consumed by the user. Non-incentivized interstitial advertisements are also common in these titles where a user is shown an advertisement for a different game and if downloaded, the developer receives a commission on the download (normally 70%). Below is breakdown of the revenue mix for a popular game My Singing Monsters.

Subscription based (Syndicated content): A less common but apple supported revenue strategy in which the user subscribes to receive content as it becomes available for a fee. This model is a well known SaaS business model that has dominated web apps over the past half decade and is now transitioning into mobile. The model comes with an organic retention increaser in the form of (I'm paying for it, so I might as well use it). The top subscription based game on iOS is The New York Times Crosswords.

Your revenue mix will be dependant on what kind of game you build. As I mentioned in our first section, the trends are moving in the direction of Free-to-play with an ever increasing number of revenue sources as the market matures.