They're touted as gas-savers, but for many people, hybrids actually won't save gas-- or money.

The Toyota Prius has a list price similar to the resale price. How can you buy a hybrid on the cheap to save gas money?

Until recently, reducing your individual impact on the environment has often been an imprecise task at best.

You could use low-energy light bulbs and make sure that your houselights were off before you left. You could carpool or take the bus to work. You could recycle.

Another option would be to do something more substantive, like forking over extra cash for a hybrid vehicle, or spending $50,000 to install electricity-generating solar panels on your roof. Unfortunately, the size of these investments tend to prohibit all but a lucky few individuals from utilizing these options.

But there is something else that can be done in order to make a difference -- use tools that accurately measure and then provide a chance to counteract the impact of greenhouse gases and other pollutants.