NEW YORK ( TheStreet) -- Amazon ( AMZN) calls them "Coins" - the company's name for virtual currency that U.S. customers can use in its Amazon Appstore. Coins, which will launch in May, are for users of Amazon's Kindle Fire tablets. The idea's that Fire owners will use these new "Coins" to buy apps, games and other in-app items on their devices. Amazon says that when the new currency launches it will be giving away millions of Coins to get things started. That way, Fire users can begin using the new currency immediately. App developers are being asked to make the appropriate changes to their software by April 25 to make sure Coins are usable at launch. What Amazon has not yet explained is the process of changing U.S. dollars into Amazon Coins. According to the press release, "Amazon will also make it quick and easy for customers to buy additional Amazon Coins using their Amazon accounts." But the release is short on actual details. Amazon assures developers that they'll continue to receive their "70% revenue share" for their apps whether buyers use credit cards or the new Coins. --Written by Gary Krakow in New York. >To submit a news tip, send an email to: email@example.com.