There is no standard formula as to what to offer for a used unit that someone is asking $75,000 for. Some dealers ask very close to what they expect to get and others mark up the product greatly. I have actually seen units priced under true value and silly consumers thinking they should discount it 40%.
Wolfe10, who actually knows what he is doing, gave you a reasonable answer. Do your research on-line as to what others are asking for a similar product and what the "book" values are. Anyone offering 40,000 for a reasonably priced 75,000 dollar unit should get one response. The salesman should laugh and go looking for a "real" customer.
