Hi,
I have noticed a rash of books being listed on ebay for well more than comparable copies on abe. There is, for example a copy of Septuagenarian Stew, HB 1st Signed 1/250 for $550. This can be had on abe for $375 (less some if you ask the seller!)
Apologies to the seller, if he is here, but I hate to see people waste their time and money listing books that they will not sell.
As a rule, the list price on abe is the bookseller price. Ebay prices should never, approach that price. When a seller starts an auction at 150% of the book seller price, I have to wonder if they have any idea or if they are "fishing for fools*"