Here's a simple, compelling argument we read in Wired that shows a used car may be a more ecologically sound choice than a new Prius:

Energy It Takes To Build Prius



113,000 BTUs







113,000 BTUs In Gasoline



1,000 gallons







Distance Driven to Break Even For Build Cost



46,000 miles







Time Needed For Average Driver to Hit 46,000 Miles



Over 3 Years







Distance Driven to Break Even with 1998 Toyota Tercel*



100,000 miles







Time Needed For Average Driver to Hit 100,000 Miles



Over 7 Years


* or any car that gets 27 mpg city / 35 mpg highway



** distance/year ratios built on 13,500-mile yearly average [Wired]