On Sat, 6 Jan 2018 06:16:23 +1100, "Rod Speed"
wrote:

Stupid IMO given that the transaction fee is just cents for those
transactions.

USA for credit cards

"In 2014, the Federal Reserve Bank of Kansas City reported that the
average merchant in the country pays around 1.73% of each credit card
transaction to the issuer, card network and other bodies that handle
the transaction of funds."
....
....
In Q4 of 2015, American Express made $4.9 billion in Discount Revenue
- their name for interchange fees....By contrast, income resulting
from interest was just $1.9 billion.

https://www.forbes.com/sites/roberth.../#420f6911a444

Gas stations seem to favor the practice because the margins on
gasoline are razor thin, if not negative, when people pay by card.

That's a myth. Look at the real merchant fee sometime.

It would not be a common practice, but most likely for those who buy
large volumes (fleets, etc) these days.

In one US state, the legislators mandated same price for cash or
credit card. Before, there was a discount for cash at many fuel
vendors. Independent vendors, small businesses, pay more to process
credit cards. I can't address what other state laws might be.

But they have to pay the monkey who accepts the cash and
that vastly more than the merchant fee on the transaction.

Most USA fuel stops are convenience stores these days, where
food/drinks/fuel are sold.

http://www.hartington.net/wp-content.../06/Caseys.jpg