Not everyone can go out and buy themselves a brand new car that has great gas mileage and is better for the environment. Even when you have the best intentions of doing what you can to help the environment and save money as well, sometimes it's simply not something you can do because of your own personal finances. Although there may be a lot less older cars on the road because of the Cash for Clunkers program awhile back, does not mean there still aren't some older cars out there that are far better on gas mileage and easier than the environment than one might think. And these cars will cost you a lot less than trying to get a brand new hybrid.
One of the best used cars still out there that gets some of the best mileage and has had three generations of good vehicles would be the Toyota Prius. The 2001 and the 2003 are the most affordable ones and are just as good as the 2004 and 2007 models when it comes to getting some really good gas mileage. The Prius will get you 42 mpg in the city and 41 on the highway.
Then there is the Honda Civic and the 2004 model holds up good against it's hybrid cousin that gets about 6 mpg more than the regular Civic. This means that you can get a car that's not all that old, for less money and still get some good mileage. In the city it will get you 29 mpg and on the highway it gets you 36 mpg for a lot less money than the newer version.
The Toyota Corolla is another great car that will save you on mileage especially if you get a coupe or a sedan. This good gas mileage is because of the smaller size of the car and it's engine. The Corolla is it's smallest model and it can get your 30 mpg in the city and up to 37 mpg on the highway. Even though it's not a hybrid powertrain it still sips the gas far better than other older cars with electric gas powertrains.
You might also be able to afford a used Toyota Camry Hybrid as well. It is their lager model and is a four door but does have a hybrid powertain and if you are looking to save gas but also have more room then the 2007 model might be one you might want to check into. The gas mileage for this car is 33 mpg in the city and 34 on the highway.
If you are looking for something even older because you still find the ones above still too much for your wallet then you might want to consider the 1999 Acura Integra it is still a good car that doesn't get the mileage like the others but it still comes in with 22 mpg in the city and 28 mpg on the highway. You also might want to check out the 2000 Toyota Echo as well, it will get you 26 mpg in the city and 34 out on the highway.