Update 9/21/16: Updated for Swift 3, iOS 10, and Xcode 8. One of the great things about being an iOS developer is the variety of methods available for making money from apps, namely: paid, free with ads, and in-app purchases. An in-app purchase (or ‘IAP‘), the focus of this tutorial, allows developers to charge users for specific functionality or content while using an app. Implementing IAPs is pa