Market overview: Which Infiniti models are currently the most popular on the used car market? AutoUncle has analysed 42 used Infiniti cars that are currently for sale at 44 dealerships. The three most popular Infiniti models as used cars are: Q30, Q70, QX30. Prices start at around £5,940, and the average price for a Infiniti on today’s used car market is £8,434.