Found this advice when browsing a UK bookseller's site.

"As from September 2002, ABE charges a percentage on the sale price of all books ordered via the 'Bookbasket' on its website, as well as a percentage on any credit card transaction processed by ABE; also, very often, postage charges and delivery times are overestimated.
We would therefore suggest, should you wish to buy a book from a seller shown on ABE, you either:

a) make an INQUIRY, clicking on the 'Ask Bookseller a Question' option which will provide a direct email link with them,
or
b) use a search engine to find if the bookseller has a site then email them direct."

No.9