Seeking more books in all forms, Amazon ( AMZN) says it will pay $300 million for Audible ( AUBL). The online retail giant has agreed to pay $11.50 a share for the Newark-based books-on-tape specialist. The deal represents a 23% premium to Audible's closing stock price of $9.33 Wednesday. Audible's share jumped 22% in pre-market trading Thursday. The news comes a day after Amazon reported a disappointing profit margin but boosted guidance for the year. Among the drags on Amazon's profits is its new venture into gadgets with a tablet device known as Kindle that lets users read digital books. Amazon shares are down 8% in the wake of the earnings release and the announcement of the Audible acquisition.