The 2021 Mercedes-Benz G-Class is available as a 4-door, 5-seat sport utility. Starting at $131,750, the 2021 Mercedes-Benz G-Class G 550 is powered by a 4.0LL , 8 - cylinder engine mated to an automatic transmission that returns an EPA estimated 17-mpg in the city and 19-mpg on the highway.