It is puzzling to see that the HP65 has a higher monetary value than the HP10 (this is an example).
Actually, many die-hard HP fans have the 65 while they are still searching for a 10.
What gives ? In this case, the items are relatively comparable : both are calculators, from the same maker, about same time frame. Obviously the feature set is wildly different.
I'd say that whatever is rare, mechanically, fetches higher price (because I can easily exchange it for the more common model).
Your thoughts ?