The Google Shopping Content Objective-C Library by Google can access API data to sell products on Google, list ads, drive traffic, and increase sales. Developers can interact with the JSON API, working with iOS 3+ and Mac OS X 10.5+. Available introduction and example applications.
Your next meal could be served up by BigOven's new API. The comprehensive service for those who like to cook provides more than 170,000 recipes in XML or JSON format (our BigOven API profile). From there, you can display it however you want, though there's a yet to be determined fee for commercial applications.