The WooCommerce PHP SDK by WooThemes allows interaction with the API, providing setup, error handling, and methods. Responses display lists of complete and single orders. Authored by Claudio Sanches and Max Rice.
Lately we're seeing a lot more talk about API monetization. Last week we covered TweetPhoto's efforts at encouraging developers to use the TweetPhoto API through a transactional payment model (one penny or so for each photo uploaded via the API). Last month we covered Bandsintown, which provides affiliate earnings via use of its Bandsintown API. And more recently Touchnote announced an affiliate payment model (with a whopping 30% royalty) for developers working with its image API.