Market prices for things Kaiser-Frazer or Willys are, of course, based on supply and demand. Trying to put a fixed price on various items will not work in the long run as the section of LAST ONSLAUGHT ON DETROIT giving a list of K-F literature and prices back in 1975.
A lot of asking prices on eBay are based on the old concept of "they are so rare the prices on their stuff should be very high". The fact that the same sellers offer the same items keep offering their goods over and over again should tell you what the buyers think of the prices. I would not recommend going into the idea of even suggesting what a piece of literature should be worth.
But that's just one person's opinion if I understand what you're trying to do here Jim.