You can now use Amazon Coins, the online retailer's virtual currency, to purchase apps, games, and in-app content on Android devices. Unsurprisingly, those purchases must all be made within Amazon's standalone Appstore; Google Play is sticking with more traditional payment options. Amazon first unveiled Coins last year and gave every Kindle Fire owner $5 in an attempt to boost the currency out of the gate. Customers can also buy Coins at a discounted rate and automatically earn extra Coins when downloading apps or by hitting achievements in certain games.

These measures are clearly meant to entice users, but we've seen little evidence that Coins are catching on. Nevertheless, and without offering any hard numbers, Amazon says it's "been amazed by the number of customers using Coins, as well as how many Coins they’re spending on apps and games." Expanding beyond Kindle Fire devices is a big step as Amazon looks to push Coins along — both to consumers and more developers. The company's Appstore app remains fairly niche in the grand scheme of Android, but it remains a good source for discounts and free apps. And now it's adding some payment flexibility, though we're still a long way off from paying Amazon with Bitcoin.