Why gas prices always end in 9/10 of a cent

[underpants]

https://www.cnn.com/2022/06/14/energy/why-gas-prices-fraction-of-a-cent/index.html

At the time, the taxes were levied in tenths of a cent and gas stations passed them on directly to drivers, said Ed Jacobson, a former gas station owner who now runs the Northwoods Petroleum Museum in Three Lakes, Wisconsin.

But why not just charge a full cent? Well, at that time, the average cost of gas was around 10 cents a gallon. So adding a cent was a big deal, especially for drivers strapped for cash during the Great Depression. Instead of rounding up, which would have equated to a 10% increase, gas stations added the fraction of a cent instead.

Just-below pricing
"A lot of the small station owners will tell you they pick a price by feel," Kloza said. "They'll tell you it makes a big difference if it's $4.999 or $5.009. Drivers don't want to see that $5."

In 1985, Iowa outlawed the practice. "We don't have a one-tenth of a coin," an Iowa state senator reportedly said at the time. "It just bugged me for years." In 1989, however, the state repealed the law and most stations returned to fractional pricing.
In 2006, Jim Davis, a gas station owner in Palo Alto, California, dropped the fraction of a penny and rounded his prices down. He said it cost him around $23 a day.

[louis-t]

1. Now if we could only get them to stop slowing the pump for the last 50 cents...

It's dark, it's 10 degrees, you're in an unfamiliar area, and the damn pump slows down to a crawl at $19.50 because the owner thinks you will just give him the last 10 or 20% of your $20 bill so you can get the Hell out of there.

[eppur_se_muova]

3. Ummm no it's for greater precison -- so it doesn't go whizzing past the right amount.

Just be glad pumps can run at two speeds now. It used to be they only ran at the slower speed. Try that at 10 degrees in the dark!

[louis-t]

4. Uh, no. The pump will shut off at the correct amount

no matter what the speed. There is no way a pump will zip past the pre paid amount. It used to slow down only the last 5 or 10 cents.

[twodogsbarking]

2. I always assumed that was their real cost and the rest profit.