I'm glad this has come up. Recently I saw some books for sale and I googled looking for a review (never buy a book unseen without a review!) First site that came up on my google search, there they were for half what was being asked here. I assumed the vendor just had no idea what they were worth- people often assume their second hand stuff is more valuable than it really us, but I was not going to take a chance on PMing the poster and saying this, as people are not necessarily going to appreciate that.
If some inexpereinced vendors are reading, they might learn something and hopefully increase their sales by pitching their price right.
And, on a tangent, have we ever had quilting book reviews on here?