2011 Nissan Sentra
Fuel economy: 30 mpg Annual fuel cost: $1,479
Total first-year cost: $16,999
With none of the buzz of the electric Nissan Leaf (our choice for greenest new car), the venerable Sentra nonetheless represents a more affordable option, though without some of the style points of other cars in its class. The automatic transmission achieves better fuel economy than the manual transmission, which gets just 24 mpg.