In response to my recent post about prices listed in fractions of cents (Frennies from heaven, 13 February), Phoebe posed a question:

Why is it that gas stations are the only ones to charge a fraction? How did that get started and why does it continue?

Yahoo made an attempt to answer that very question, but they found no concrete explanation; “Theories abound, but none are definitive,” they say.  But they don’t leave us high and dry; they do helpfully list the theories, and it seems most believe it is simply a marketing gimmick.

(Most interestingly, they do note that Canadian gas stations do the same, but with a twist: Canadian stations don’t always end their prices with .9.)

I hope that provides you some peace of mind.