What is a Book Worth II

I have tried to create formulas to determine the fair market value of used and rare books. Thus far my formula is simplistic, and does not entirely work. However, it works to the extent that it can give a prospective bookseller an idea of whether or not a book might be worth doing some work on - that is, research into values.

P = C x (# + S)

Price = Condition times the numbers of collectors - in fiction; or numbers of types of collectors, plus the specificness of the title.

Sadly, this does not include so many unpredictable factors, such as a media event to drive up or down the value.

When creating a "list" price for new titles, it is not unusual for publishers to use the formula: P =( UC + F) x 8. That is, the list price equals Unit cost, plus Freight costs, times eight. Would that rare and used books could be so predictable.