A new service launched by Amazon allows Android game developers to sell physical items through their games.
Currently available for Android (including Kindle Fire), Amazon Mobile Associates API allows developers to sell real products from the millions of items at Amazon, whether physical (i.e. toys, clothing) or digital (i.e. eBooks), from inside their apps or games while earning up to 6% in advertising fees from those purchases.
The API can be used to sell a specific item such as game-themed t-shirt or a category such as vitamins and supplements.
Games that use the API have already made to the market. For example, Animoca's Thor: Lord of Storms game for Android now offers Thor physical action figures to its customers. More interestingly Ticket to Ride developer, Days of Wonder, allows its players to purchase a physical expansion pack of the board game and get the digital version for free.
Technical details and development guides are available at Amazon's developers portal.