Unlock built-in content based on in app purchase. Create a tab based application with 4 tabs. The third tab will have the a list of content available for purchase listed in a table. When they select a particular content cell, list the details of that content and a button to purchase the content. Once they purchase the content it will be unlocked using the plist file, so that the purchased content will now appear in the first tab in a table view. Once the user purchases make sure that it is not presented to the user again for purchasing the same thing.