It's easy to be ripped off the net if you don't look around at similar web-sites before deciding to buy a product. When a publisher releases a book, then quite naturally, they slap a price on the book. A price which all book sellers should sell the book at. But looking around the net you'll find price differences of up to $5 [same book!] Why do some book sellers hike up prices? Do they get lower bulk discounts so they just have to make some extra money from an unsuspecting buyer?
I don't believe an author can state a price if another site is selling their book, a bit like a local shop selling bars of chocolate for whatever price they want, they have bought the chocolate from the warehouse so it is up to the store owner to determine a price.
You might want to make sure that the edition and publishing format is the same for each of the books you are looking for. My bf is incredibly picky about buying his series fantasy collections. He prefers collector trade paperback editions, which are larger, with special matte finishing and different paper, and they look great on the shelf. There are little tiny hardcovers editions, and obviously hardcover can be easy to spot vs paperback, but the trade paperbacks vs the smaller editions vary greatly, the smaller versions are printed on cheaper newsprint rag, and not as valuable to collectors.
