This could be used to buy apps and games, or make in-app purchases.
Of course, being Amazon, it's not giving out any hard figures on how the experiment went.
We don't even know officially how many Kindle Fire tablets it's sold.
But Amazon's obviously pleased enough for technical evangelist Peter Heinrich to take to the Amazon developer blog and talk about the move.
"The customer reaction has been great," he said.
"Customers already spent hundreds of millions of Amazon Coins, representing real dollars to developers, who still received their 70 percent revenue share."
(For the record, 100 Amazon Coins are currently worth about $1, so the amount spent is 'millions of dollars'.)
Jumpstart the economy
In addition, Amazon said that "for almost half of developers who monetized their Amazon apps using Coins, weekly revenue jumped more than 50 percent after the announcement".
Trying to draw any conclusions from such loose 'facts' is nigh on impossible, although Fruit Ninja developer Halfbrick commented that, "We saw a significant increase in revenue after the Amazon Coins announcement.
"Revenue from Amazon Coins during the launch week was higher than previous week's revenue. What was also interesting is that our cash receipts also saw a lift from Coins," it added.
Platform-wide wallet
Still, the point Amazon is trying to make is clear.
"For some indie developers, Coins already account for the majority of their revenue," it said.
For the cynical journalist, this could just mean that Kindle Fire users didn't monetised heavily when asked to spend real money to make virtual transactions of the platform.
Either way, it suggests the company will continue to push Amazon Coins as a powerful lever to get users spending.
After all, neither Apple or Google has a virtual currency that can be use across the apps and games on their app stores to make purchases or in-app transactions.
And with Amazon now allowing users to buy Amazon Coins in bulk - $90 for 10,000 is the current maximum - it looks likely the online retailer will be thinking up new ways to better layer real-money and virtual currency transactions.
