The 2004 Nissan Altima is available as a 4-door, 5-seat sedan. Starting at $16,850, the 2004 Nissan Altima 2.5 (50 State) (M5) is powered by a 2.5L, 4-cylinder engine mated to a manual transmission that returns an EPA estimated 23-mpg in the city and 29-mpg on the highway. The top of the line 2004 Nissan Altima Base, priced at $17,350, is powered by a 2.5L, 4-cylinder engine mated to an automatic transmission that returns an EPA estimated 23-mpg in the city and 29-mpg on the highway.