With Lemonade Stand, users can search for things to buy in a location-based manner, or add their own listings of things they wish to sell. The application is currently available as a client for Android, with a possible Windows Phone 7 version on the way soon as well, from a 3rd party developer that released an early version. Its Lemonade Stand API allows other developers to either code their own clients or use it in mashups.
Shopify has replaced its legacy Discounts API with the New Price Rules API. The API keeps what worked from the Discounts API, and greatly enhances those features with more flexibility and capability. One and five Shopify sales includes a discount of some sort, and Shopify wants to capitalize.