Amazon has contacted some of its US customers to offer partial refunds for e-books bought between April 2010 and May 2012.
The compensation – $0.30-$1.32 (20p-80p) per title – is the result of a settlement between publishers and the US authorities.
Barnes & Noble is expected to email its customers with a similar offer soon.
Several e-book publishers – plus Apple – were accused of colluding to fix and raise prices.
Customers covered by the settlement will not receive refunds until a hearing approving its terms takes place in February next year.
The compensation will cover titles produced by three major publishers – Hachette, HarperCollins and Simon & Schuster. The firms have together raised a fund of $69m to pay the fees.
Two other publishers, Penguin and Macmillan, declined to agree to the settlement and will instead be taken to court, along with Apple.
Source: BBC News