First of all, you can find used car listings on your local newspapers website. These are nice, because they are all typically sellers in your local area which makes it easy to stop by and take a test drive, which is critical for getting the best possible deal on a used car.

Stepping out a little more, you can check online classifieds sites, such as Craigslist, which will expose you to a broad range of sellers, many of whom will be near you, though not to quite the same extent as a news paper might. These sites can be gold mines, though, so be sure to give them a look.

If you're looking to broaden your scope further, try sites like eBay Motors, which brings sellers from all over the country into one convenient location. These listings are both auction format and fixed price, so you have multiple buying options. These sellers will be located all over the country, but you can search for listings that are in your area. What's more, eBay offers some basic protection for its buyers, which helps prevent major rip-offs. Definitely worth checking into.

If you're looking at a very specific model of car, try search on car enthusiast forums. For example, if you want to buy a late '80s Nissan Z car, then visit some Z car forums to find sellers. Buying from these sorts of sellers can be great, because they are often very knowledgeable and passionate about the cars. You will be able to get a really good idea as to the condition of the car if you go with a seller like this.

There are many other places to find used cars online. In fact, there are many other car listing specific sites you can buy from. However, the places I've listed above have the highest amount of listings, and are thus the most "bang for your buck" locations for buying a used car online.

As always, be careful when shopping online. Don't throw away your common sense, and make sure that you're getting a good car at a fair price. If you do your research, check multiple sources for pricing, and check the car over thoroughly for buying, you can certainly buy used cars online and get great deals for it.