I filled up my car today at $1.999 a gallon. What is the point of the little 9 in the price? Where did this start?
It’s a marketing trick to make you think the gas is cheaper than it is.
Here’s one cite that claims the convention dates to the 1920s.
In places where fuel is sold in liters, the price is still quoted to the tenth of a cent/euro/whatever, but the tenth number actually changes to something other than 9. Theoretically this could happen here, but it doesn’t.
Wouldn’t it be awesome if gas stations started price wars with the thousandth of a cent? I mean, one gas station sellsregular at $2.209, and the one across the street undercuts it by selling at $2.208? Wouldn’t that be funny?
Obviously, I have nothing intelligent to add to this thread.
I assume they’re allowed to do this because gas is sold in bulk, not discrete amounts. Otherwise, it would be false advertising - if you bought exactally one unit at $1.999, you wouldn’t receive any change, so they are misrepresenting the price. But since gas isn’t sold in discrete units, they’re in the clear, legally speaking. But it’s still annoying.
Actually, most of the time, it’s a lie to boot. I remember testing this when gas was exactly 0.999 a gallon (those were the days). I’d fill up exactly 10 gallons (to the thousandth), and I’d be charged exactly $10.00. not $9.99 like I should have been! I want my penny darnit! 
I always thought the thousandths of a dollar was part of the tax tacked onto each gallon. Say the station charged 2.00 per gallon and the taxes were another 23.9 cents. That would make the gallon cost $2.239.
Nope. Gas taxes vary from state to state but pretty much every station in the country uses the .9 pricing convention.
I would think it makes some sense now as gas is metered to the thousandths of a gallon, so pricing it to a thousandths of a dollar would match up nicely.
I promise to buy my gas from the first station that raises their price by one tenth of a cent. I’ve always been annoyed by the 0.9 cents in the price. It may have fooled some people in the old days, 32.9 cents does seem cheaper than 33 cents, but 205.9 cents isn’t that much below (percentage wise) than 206 cents.
Well since the average usage a day in the US is 360 million gallons that .9 cent works out to $1,182,600,000 per year to the retailers.
It’s $1.49 and 8/10ths of a cent at Donny’s Discount Gas.