Amazon is set to release a payment system based on virtual coins in its Kindle AppStore.

The payment system will allow Kindle users to buy apps, games, and in-app purchases using virtual currency. Amazon says the coin-based system will help developers increase the monetization of their mobile applications.

Amazon will drop the virtual coins onto the market in the US in May. To increase usage of the currency the firm will be offering millions of dollars in free coins to consumers at launch.

One Amazon Coin will be the equivalent to one US cent of real currency. For instance, an app priced at $2.99 would cost 299 Coins.

Coins are being touted as a way to increase sales for app developers. Amazon says the virtual currency is an easy alternative to traditional payment methods.

"Developers continue to report higher conversion rates on Amazon compared to other platforms," said vice president of apps and games for Amazon Paul Ryder.

"Now we have another new way to help developers reach even more of our millions of customers. Amazon Coins gives customers an easy way to spend money on developers' apps on Kindle Fire in the Amazon Appstore - and we're giving customers tens of millions of dollars in Amazon Coins to get started."