Usually found in games or dual-licensed apps, this kind of payment system is used to allow users access to premium-like features only after a fee has been paid.
A demo is included with the download package.
Here are some key features of "iOS In-App Purchases":
- Payments handled via the App Store in-app purchase service
- Management of purchased products
- Can remember already purchased goods
- Supports Apple's "Restore purchases"
- Shows an in-app purchase menu
- Tracks every aspect of the purchase (requests, transactions, restores, etc.)