This is Part 1 of a 5-part back-and-forth between my friend Jason and myself as we compare the eco-friendliness of the Kia Soul and the Toyota Prius.

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.

When I purchase a commodity, I want it for the lowest price. When, I purchase a non-commodity, I am looking for the greatest total value (quality/cost).

As the democratization of information has evolved, and with the help of my friends at Consumer Reports, this has made my purchasing decisions over the last 5 years extremely rewarding.

But, today, I am in the market for a mattress. And I am learning that, unlike nearly all other retail purchases, consumers have no power in the mattress-buying process.

It's uniquely impressive. These mattress companies have figured out how to avoid the ability to comparison shop altogether. For example, when Sealy sells a mattress through Sears, they might name it Ultraplush 2100. When Sealy sells the exact same mattress through American Matress, they name it ComfortMotion.

I can't figure out how to objectively determine the best quality sub-$600 king-size mattress out there. It's infuriating. It's brilliant.

Any advice?