When looking online to find fuel efficient cars, your first stop should be the US government's own website dedicated to the issue, http://www.FuelEconomy.gov.

Just about every question imaginable related to fuel economy and greener driving is addressed at this website.

Thinking of buying a more fuel efficient vehicle? No problem. Want to know the cars with the best and worst fuel economy? They have that covered. Don't know the differences between hydrogen power, diesel, fuel cells and/or ethanol? They can help you out there, too. On everything from tips on hyper-miling in your Honda Insight to explaining tax incentives for buying hybrid cars, the site is a one-stop shop.

One of the most helpful features of the site is their efficiency breakdown of individual cars. Suppose you drive a 2-door 2008 Toyota Yaris. FuelEconomy.gov will tell you the car's fuel economy (29 in the city/35 on the highway), environmental impact and carbon footprint (5.7 tons of CO2 a year), yearly fuel cost ($1146), cost to drive 25 miles ($1.91), cost of a fill-up ($24.38), and pollution score (Good). If you are thinking of purchasing a car, the site will also let you compare makes and models side-by-side so that you can see which cars wins out in the long term. You can also browse cars by MPG (high to low) or by make and model.

One thing FuelEconomy.gov doesn't provide, however, is current market pricing of individual models. For that information, your best bet is to turn to a site like CarMax.com, the website for nation-wide used car dealer CarMax. This site is handy because CarMax sells all makes and models of car, meaning that you can compare prices across the board all at one website. The site makes browsing by MPG especially easy, allowing you to choose a car based on city or highway mileage.

Between the government's site and Carmax's site, you should have plenty of information available to you about car fuel economy and choosing the car that is right for you. Happy reading.