I bought far more eBooks on impulse when they were all $9.99.  When they break above $10, I have to think before I buy, and I buy less often.

The skirmish over prices is possible because of deals that publishers negotiated with Amazon this year that allowed the publishers to set their own prices on e-books, while Amazon continues to choose the discount from the list price on hardcovers.

That upended a previous understanding by Kindle customers, who were used to paying only $9.99 for an e-book.

“Amazon’s bait-and-switched us here,” said Janice Dinse, 63, a medical transcriptionist in Gastonia, N.C., who complained about the price on the novel by Mr. Patterson. “When I first got my Kindle, all the books were $9.99. I’m not going to pay for a book on my Kindle that’s more than $9.99. I just refuse to do it. I could buy the hardcover for that if I go to Sam’s or Wal-Mart.”

Amazon has tried to direct customer wrath over e-book prices at the publishers. After prices began to rise this year, routinely landing at $12.99 to $14.99, Amazon alerted readers by adding a line in italics below the Kindle price: “This price was set by the publisher.”