Lifehacker Rule of Thumb: It costs a dollar to drive 7 miles

http://lifehacker.com/5876890/10-things-you-do-to-save-money-that-end-up
-costing-you-more?popular=true
Here's the one that really caught my eye, because I know a lot of people
who drive across the river to Council Bluffs to fill up on gas because
it tends to be 10 cents a gallon less than here in Omaha. I never
understood that (buying gas WHILE you are in Council Bluffs for other
reasons does make perfect sense, of course):

8. Driving Miles and Miles for Cheaper Gas or Other Bargains
At the time of writing this article, the average cost of a gallon of
regular gasoline is $3.28. And the average vehicle MPG is around 23.
That gives you around 7 miles for every dollar you spend on gas. Do the
math. For example, if you want to put 10 gallons of gas in your car, and
drive four miles out of your way to buy gas that is five cents cheaper
per gallon, you have spent 57 cents to save 50 cents. And you've wasted
your time, put more wear on your tires, and used up oil life as well.
True, it's not a lot, but in the grand scheme of things, it's just not
worth it. I've also talked to people who traveled 30-40 miles, one way,
to buy something used from Craigslist. So right there, you're adding up
to $10 to the cost of the item you're buying.