The 2015 Mercedes-Benz GLK-Class is available as a 4-door, 5-seat sport utility. Starting at $39,900, the 2015 Mercedes-Benz GLK-Class GLK 350 AWD is powered by a 3.5L , 6 -cylinder engine mated to an automatic transmission that returns an EPA estimated 18-mpg in the city and 25-mpg on the highway. The top of the line 2015Mercedes-BenzGLK-ClassGLK 250 BlueTEC AWD , priced at $ 39,400 , is powered by a 2.1L , 4 - cylinder engine mated to an automatic transmission that returns an EPA estimated 24-mpg in the city and 33-mpg on the highway.