Thanks to an antitrust settlement, Amazon is issuing credits to customers who purchased Kindle e-books between April 2010 and May 2012.

Amazon sent out emails on Tuesday, telling customers, "Good news! You are entitled to a credit of $[amount] for some of your past Kindle book purchases," NBC News reported.

The money stems from a 2012 Department of Justice lawsuit alleging that Apple and five major book publishers were working together to inflate the price of e-books. The antitrust lawsuits were brought by a coalition of state attorneys general, not Amazon itself.

The publishers, which included Hachette, HarperCollins, Simon & Schuster, Macmillan and Penguin, all reached settlements with Amazon in December 2013, but Apple has appealed the federal judge's ruling. The five book companies are funding the Amazon credits.

The controversy came after Amazon launched a discounted e-book price in 2007, making many Kindle books available for $9.99. The publishers allegedly went to Apple to collude and force Amazon to raise e-book prices in January 2010, right before Apple launched the iPad, NBC News reported.

Apple is still contesting the case, Mashable reported.

Customers who received Kindle money will earn credits of $3.17 for each purchase of a New York Times bestseller during the specified time and $0.73 for other books. The credits are good until March 31 of next year, according to Mashable.

Those who earned credits won't have to do any extra steps, since Amazon has already applied the money to their accounts. The credits will go toward their next Kindle e-book or print book purchase, NBC News reported.

Amazon has published a customer FAQ regarding the settlements that is on the website. A summary of the lawsuits and the settlements is also available online. 

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