One of the advantages of buying a used car is that it often allows the driver a little wiggle room in terms of negotiating. Drivers can attempt to haggle over a new vehicle, but most of the time those prices are dictated by the automaker. But when shopping used, buyers with some negotiating skills can often get themselves a great deal.

ABC News recently teamed up with Philip Reed, the senior consumer advice editor for Edmunds.com in order to learn some top negotiation strategies. The auto website buys quite a few cars for research and testing purposes, and Reed is usually the one doing the purchasing. Reed has also seen both sides of the negotiating table, even working as a car salesman as part of an undercover experiment.

The website was in the market for a used Honda Odyssey EXL from 2007. They gave Reed a budget of $25,000 and wishes for a low mileage, well-maintained vehicle with a sunroof for easier photographing. Reed allowed the news source to tag along as he went to several dealerships in an effort to snag the best price.

Many buyers assume that the negotiation process doesn't start until drivers are brought into an office and start going over paperwork. But according to the news source, the first number talked about is often the most important. A good salesman will try to get the buyer to name their price first. That way, they can work from there and hopefully raise the eventual price of the vehicle. But if the buyer gets the dealership to name the price first, they can work down from there.

A good strategy to compliment this is to use a pricing guide. A buyer should go in with a price in mind, but resist revealing it to the salesperson. It's easier to slowly work a salesperson down from their price than get them to stick to the buyer's.

Another tactic is to make sure to always leave the dealership. Even if it seems like a great deal, leaving the dealership and shopping some other car lots can't hurt. In fact, it can be beneficial to quote another dealer's price in order to get another to come down in price.

Using these and other tactics, Reed was able to negotiate the price of the used Honda down from $25,000 to $21,500 – a savings of $3,500. With a little research, drivers can do the same and get a great deal on a used car today.

As more people become concerned about global warming and other environmental issues, many drivers consider the eco-footprint of their vehicle to be an important factor in making their decision. While miles per gallon is one way to rate how fuel efficient the car is, it doesn't get to the heart of the issue – namely, how much smog-forming emissions the car produces.

The Union of Concerned Scientists releases yearly rankings that look at all the vehicles that an automaker offers in a particular year, then names which one is the "greenest" overall. It does this by averaging various environmental factors and rolling it into a composite overall score. This year's study looked at cars from the 2008 model year, as it was the most recent year that full data was available to the group. The group only looks at the top eight companies in the U.S. – Honda, Toyota, Nissan, Ford, GM, Chrysler, Hyundai and Volkswagen – in determining the rankings, as these account for over 90 percent of the vehicles on American roads.

For the fifth consecutive year, Honda was named the greenest automaker by the study, but it just narrowly beat out competitors Toyota and Hyundai, who tied for second place. Just one point separated the three companies, with Honda scoring an 86 and the other two at 87 (lower scores are more desirable).

"It was a photo finish, but Honda is still the champ," said Jim Kliesch, author of the report.

Despite the victory for the 2008 year, Honda will likely drop off once the latest plug-in hybrids hit the market. While Honda has announced two plug-in models for 2012, those will likely come after many competitors have introduced their offerings. Honda believes the plug-in craze to be a stopover before the greenest technology is introduced: hydrogen. As such, the automaker is devoting more resources toward developing those cars.

"We feel that it's the ultimate solution," Honda spokesman Chris Naughton told CNN in July "But the infrastructure is developing more slowly than we had anticipated."

The study noted that many predicted Toyota to take the top spot from Honda this year, but the automaker stalled in adopting carbon-reducing technology. Hyundai, meanwhile, shot up the rankings by emphasizing more efficient vehicles with smaller four-cylinder engines.

The rankings were not good news for Detroit's "Big Three." Chrysler, GM and Ford finished in the bottom three spaces, with Chrysler placing dead last. The study did note that environmental standards were up overall and that the American companies could see their rankings climb thanks to future introductions like GM's Chevy Volt.

Drivers can likely find many of the 2008 models that were evaluated in the study on the used car market. Buying a used hybrid can make sense because the reduced price of the pre-owned market can offset the inflated price that many drivers pay when buying the vehicles new.