I know its simple math. For instance I was looking at 2005 Honda Accord vs. 2005 Honda Accord Hybrid. There was about 10,000 dollar difference in price. Just think about it how much would it cost a person to fill a regular Honda accord vs a Honda Accord Hybrid a week. I think its around $8 difference. Now you times that by 52 weeks a year, and that gives you a little over $400 a year savings.
So the question should be do I spend 10K on a Hybrid to save $400 a year? Of course not... Hybrids are still in their infant stages. 10 years from now they maybe more reasonable, but for now no way...
You'd be surprised (or maybe you wouldn't, LOL) how many fairly intelligent people are running around right now planning to pay that $10,000 difference for the hybrid -- to save $400 per year in gasoline.
You missed one scenario. Suppose you were limited to being able to buy 10 gals a week.
Does your decision matter?