Amazon Coins is a virtual currency that you can use to buy apps or supported apps that use the Amazon SDK to make in-app purchases. The big different between Coins and just using your credit card is that you can always get discounts. Speaking of which, Amazon is currently running a promotion where you can save 20% of all Coin bundles for a limited time.
Michael Kozlowski is the Editor in Chief of Good e-Reader. He has been writing about audiobooks and e-readers for the past ten years. His articles have been picked up by major and local news sources and websites such as the CBC, CNET, Engadget, Huffington Post and the New York Times.