Well, there are some crazy sellers counting on the uninitiated. Zone VI workshop can be had today from $10 to $90. Same goes for many titles. I usually check Abesbooks.com, as it seems a good market indicator for any particular title, far outdoing Amazon in this regard. So, if you think you have a gold mine in the basement, check the market because most of these aren't going for much.
BTW, Simmons' View Camera isn't a 1957 DeSoto, not even close.