In-App Purchase Samples
This sample contains four projects:
Consumable purchases docs
Non-Consumable purchases docs
Non-Consumable purchases using iOS 6 hosted content docs
ProductView using iOS 6 feature purchase iTunes/App Store/iBookstore content in your app docs
There is also a directory containing the Xcode projects that are used to build Hosted Content for iOS 6 in-app purchases.
NOTE: it does NOT demonstrate RECEIPT VERIFICATION, so you'll have to add this in yourself.
You might also consider services like http://urbanairship.com/ or http://www.beeblex.com/ (although I have not tried them, so can't recommend).
Check out @redth's server-side code to help build your own receipt verification logic with ASP.NET:
FYI the sample code is based in-part on @jtclancey's AppStore code here:
Store Product View
This sample demonstrates the new iOS 6 SKStoreProductViewController that lets applications display iTunes, App Store and iBookstore products for review or purchase.
There's a bit of set-up required for In-App Purchases (registering your bank details with Apple, setting up the products in the iOS Developer Portal, Provisioning your app correctly). These steps are the same for MonoTouch and Objective-C, so Apple's setup doco might help . You should also read Apple's In-App Purchase programming docs , for familiarity.