Wade,
Nothing is fishy here. Remaindered books are books that are no longer selling well and whose remaining unsold copies are being liquidated by the publisher at greatly reduced prices. While the publisher takes a loss on the sale of these books, he's able to recoup some money and clear out space in his warehouse. A book that might retail for $20.00 will typically be purchased by someone specializing in remainders for $1.00 and then be resold for approximately $5.00. You'll see tables full of remaindered books at Barnes & Noble and other similar booksellers, usually marked as "sale" or "bargain" books. Daedalus is another seller specializing in remaindered books and CDs. I've bought hundreds of such books from Mr. Hamilton over the years including, as I said above, volumes 2 & 3 of La Grange.
EDIT: I should add that I recently ordered and received two copies of La Grange's Volume 4 from Mr. Hamilton (one for my library and one intended as a gift) and they are absolutely identical to the books currently being sold by Amazon for $94.50.
James