The 2008 Mercury Mariner Hybrid is available as a 4-door, 5-seat sport utility. Starting at $29,920, the 2008 Mercury Mariner Hybrid 4x4 is powered by a 2.3L , 4 -cylinder engine mated to an automatic transmission that returns an EPA estimated 29-mpg in the city and 27-mpg on the highway. The top of the line 2008MercuryMariner HybridFWD , priced at $ 28,150 , is powered by a 2.3L , 4 - cylinder engine mated to an automatic transmission that returns an EPA estimated 34-mpg in the city and 30-mpg on the highway.