If you buy ebooks on a Kindle or Nook, you may have free credits waiting for you the next time you make a purchase.

Amazon on Tuesday began issuing partial refunds for ebooks bought between April 1, 2010, and May 21, 2012, as part of a settlement of a lawsuit over price-fixing involving five publishers. As readwrite reports:

The settlement comes after a federal judge found Apple guilty of price-fixing ebooks in conjunction with five publishers including Hachette, HarperCollins, Simon & Schuster, Macmillan, and Penguin. Although the credits are being applied to Amazon customers accounts, the actual settlement is being paid by the publishers. 

The credits will be either $3.17 per ebook for New York Times bestsellers or $0.73 for non-bestsellers (Minnesota claims were settled separately, so residents there get $3.93 or $0.94, respectively). You can check your credit status at Amazon.com.

Amazon has posted more information about the settlement on its website.

But Amazon isn't the only retailer involved in the class action suit. Other ebook retailers include Google, Barnes & Noble and Apple.

Barnes & Noble also began issuing credits for its Nook customers on Tuesday. The company posted an FAQ about the credits to its website. You can also look up your settlement ID if you have one.

Apple is challenging the judge's decision in court, and if it loses, it ultimately stands to lose between $697 million and $840 million, according to Publishers Weekly.

How much was your refund? Let us know in the comments or tweet us @kpcc!