The 2015 Buick LaCrosse is available as a 4-door, 5-seat sedan. Starting at $33,635, the 2015 Buick LaCrosse Base FWD is powered by a 2.4L , 4 -cylinder engine mated to an automatic transmission that returns an EPA estimated 25-mpg in the city and 36-mpg on the highway. The top of the line 2015BuickLaCrosse1SV FWD , priced at $ 31,065 , is powered by a 3.6L , 6 - cylinder engine mated to an automatic transmission that returns an EPA estimated 18-mpg in the city and 28-mpg on the highway.