There are many factors that influence what price a car will sell for...
ANY car will sell for whatever someone is prepared to pay for it,
or for whatever the seller will take, which can also depend on how
desperate he/she is to sell it.
Also what has to be borne in mind is the location/area it is being
sold in, together with the time of year (close to Crimbo is a no-no),
and on the economy/state of the country at the time.
And finally, availability of the car; as in rarity value; will also influence
the price.