The 2010 Mercury Mariner Hybrid is available as a 4-door, 5-seat sport utility. Starting at $30,105, the 2010 Mercury Mariner Hybrid FWD is powered by a 2.5L , 4 -cylinder engine mated to an automatic transmission that returns an EPA estimated 34-mpg in the city and 31-mpg on the highway. The top of the line 2010MercuryMariner Hybrid4x4 , priced at $ 31,855 , is powered by a 2.5L , 4 - cylinder engine mated to an automatic transmission that returns an EPA estimated 30-mpg in the city and 27-mpg on the highway.