In a conference call with analysts about third-quarter results, Amazon.com chief financial officer Tom Szkutak said the e-tailer has begun testing "even greater discounts" for books "that meet certain price points and elasticity criteria." Books over $15 are now discounted at 30%. The company has also begun offering customers an additional 1.5% discount when they use Amazon's new A9 search engine.

Sales in Amazon's North America media group, which includes books, rose 12%, to $563.6 million, for the third quarter ended September 30. The increase was slower than the 15% increase posted in the third quarter of 2003. Bestselling products in the group were the Star Wars Trilogy DVD and Jimmy Buffett's newest CD. Earnings in the segment in the quarter fell by $5 million, which the company attributed to an increase of $7 million in its net shipping loss. Customers using free shipping reached record levels in the quarter, said chairman Jeff Bezos, and the company will continue to push the free shipping option.

Sales in the worldwide media group rose 41% in the quarter, to $530.3 million.

Szkutak also said that third-party unit sales represented 28% of worldwide units, up from 22% in last year's third quarter.

For the nine-month period, sales in the North America media group rose 12%, to $1.70 billion, while international media group revenue increased 46%, to $1.60 billion.