Market overview: Which Porsche models are currently the most popular on the used car market? AutoUncle has analysed 211 used Porsche cars that are currently for sale at 46 dealerships. The three most popular Porsche models as used cars are: Cayman, Cayman GT4, Cayman S. Prices start at around £13,590, and the average price for a Porsche on today’s used car market is £36,825.