Understanding Apple's In-App Purchase System for Account-Based Subscriptions: A Practical Guide

Understanding StoreKit and Payment Queue in iOS: Why `paymentQueue:updatedTransactions:` is Not Called When a Transaction Updates

Handling Multiple Transactions with Different Prices Using a Single IAP ID on iOS with App Groups

Building a Mobile App for Selling Ebooks: A Comprehensive Guide to Apple's In-App Purchase Model and Alternative Payment Solutions.