Best way to implement in app purchases

Whats the best way implement in app purchases?

It's not just any kind of in app purchases. For that I can follow this tutorial. I'm trying to make something like what uber has. Someone posts themselves up with a fee. If someone wants that person, then he pays him, and uber gets a percentage.

For example. If the driver charges $10, and someone pays him, then uber gets %25.

Question

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  I would like to know what service works best for this? (ex. paypal, apples in app purchase etc.)

  
  


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  And how to implement it? Maybe send a link to a tutorial.

  
  

Hope I made myself clear. If you have any questions, please ask.