Market overview: Which Porsche models are currently the most popular on the used car market? AutoUncle has analysed 227 used Porsche cars that are currently for sale at 44 dealerships. The three most popular Porsche models as used cars are: 718 Cayman, 718 Boxster, 718. Prices start at around £29,990, and the average price for a Porsche on today’s used car market is £54,014.