My friend recently bought a used Toyota Prius. He is a consistently eco-friendly guy (puts more miles on his bike than he does on his car, is a vegetarian, and loves the Prius' design ingenuity).
I recently bought a new Kia Soul, which offers a similar design, but not nearly the miles-per-gallon benefits.
The used 2008 Toyota Prius cost my friend $17,000 and gets 48 highway mpg.
The new 2011 Kia Soul cost me $16,500 and gets 31 highway mpg.
Who made the more eco-friendly purchase?
Note: If you can guess what the crux of my argument will be, you win a point.