Too Long; Didn't Read
<a href="https://support.apple.com/en-us/HT202023" target="_blank">In-app purchase (IAP)</a> is a great way to earn money from your iPhone, iPad, iPod touch or Mac app. You can detect if some app offers <a href="https://hackernoon.com/tagged/iap" target="_blank">IAP</a> by going to the app page, and see if it has “Offers In-App Purchases” or “In-App Purchases” near the Price, Buy, or Get button. IAP is mostly used to unlock some extra content in your app that you want to monetize from. Like it or not, Apple charges 30% of each successful transaction that your app will make.