The 2012 GMC Sierra 1500 Hybrid is available as a 4-door, 5-seat regular side. Starting at $40,010, the 2012 GMC Sierra 1500 Hybrid 3HA 4x2 is powered by a 6.0L, 8-cylinder engine mated to an automatic transmission that returns an EPA estimated 20-mpg in the city and 23-mpg on the highway. The top of the line 2012 GMC Sierra 1500 Hybrid 3HB 4x4, priced at $49,990, is powered by a 6.0L, 8-cylinder engine mated to an automatic transmission that returns an EPA estimated 20-mpg in the city and 23-mpg on the highway.