Recently, Amazon announced the release of new plugins for Unity, which will allow developers to easily integrate the “Amazon” In-App Purchasing and GameCircle APIs into their games on this engine.
This toolkit is part of the latest version of the Amazon Mobile App SDK, distributed for free.
Recall that IAP support appeared in products for the Amazon AppStore in April. The GameCircle social gaming platform (to some extent an analogue of the iOS Game Center, was launched in July of this year.