The 2021 GMC Sierra 1500 is available as a 2-door, 3-seat regular side. Starting at $30,000, the 2021 GMC Sierra 1500 4x2 Regular Cab is powered by a 4.3L, 6-cylinder engine mated to an automatic transmission that returns an EPA estimated 16-mpg in the city and 21-mpg on the highway. The top of the line 2021 GMC Sierra 1500 Elevation w/3VL 4x4 Crew Cab 6' Box, priced at $47,000, is powered by a 2.7L, 4-cylinder engine mated to an automatic transmission that returns an EPA estimated 18-mpg in the city and 21-mpg on the highway.