The importance of in-app payments within online payment processing industry is growing rapidly. In recent years we have witnessed the emergence of several technological approaches to handling of in-app purchases.
Are you a developer of mobile apps, through which you need to accept payments? If the answer is yes, you have to analyze several important factors to decide, which of the approaches is most suitable for your business model.
Beside implementation costs, you need to remember about the prospect of having (or not having) to go through PCI audit, availability (or unavailability) of payment information. Based on these considerations you can choose one of the options: directly integrate with a third-party payment gateway, use the services of an app marketplace, use AndroidPay/ApplePay, or accept payments through a payment page or third-party wallet.
If you need more information about the ways of accepting in-app payments, read the respective article on Paylosophy.