Market overview: Which Mini models are currently the most popular on the used car market? AutoUncle has analysed 3,285 used Mini cars that are currently for sale at 46 dealerships. The three most popular Mini models as used cars are: Cooper Countryman, Cooper S Countryman, Countryman. Prices start at around £4,349, and the average price for a Mini on today’s used car market is £19,073.