The 2011 Mercury Mariner is available as a 4-door, 5-seat sport utility. Starting at $23,565, the 2011 Mercury Mariner Base FWD is powered by a 2.5L , 4 -cylinder engine mated to an automatic transmission that returns an EPA estimated 21-mpg in the city and 28-mpg on the highway. The top of the line 2011MercuryMarinerPremier 4x4 , priced at $ 27,385 , is powered by a 2.5L , 4 - cylinder engine mated to an automatic transmission that returns an EPA estimated 20-mpg in the city and 26-mpg on the highway.