Online Gambling app Fee structure

Hello, I am writing a research paper for my college marketing class and was hoping to get some insight as to the cost structure applicable to an online gambling app. The hypothetical app in question is an app in which users are able to use real money to bet on games but I can not find a cost structure besides the common in app purchase revenue sharing model of 30%. Is this still applicable in this hypothetical case or is an alternative revenue sharing model applicable due to this app's unique structure. Furthermore, would this fee be taken from bets (due to the apps losses) or from all realized profits?

Online Gambling app Fee structure
 
 
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