Has "No 9/10" been tried?

It has been nearly 100 years. Why is the silly 9/10ths still here?

Yes, the concept of a "no 9/10ths" gas price has been tried before, both at a legislative level and by individual retailers.1

The previous attempts included:

• Iowa State Ban (1985): The state of Iowa banned fractional pricing for gas, requiring stations to use whole cents. However, the law was repealed just four years later in 1989 because it was unpopular with station owners who felt they lost a competitive edge to neighboring states.1

  
  

•   Individual Chains: Occasionally, small chains launch "No Fractions" marketing campaigns as a gimmick, but they typically revert to the standard $9/10$ model once the campaign ends.1

  
  

The documents attribute the persistence of the $9/10$ model to the "Left-Digit" Effect (making $3.49 look significantly cheaper than $3.50) and the fact that the small fraction adds up to a large amount of annual revenue for the U.S. fuel industry (estimated at around $1.2 billion to $1.5 billion per year).1