When I was in High School I worked for JC Penney, in the shoe department.
Not only did we have manual cash registers, we also had a till for pesos in addition to dollars, but that is a different story. This was in El Paso, back in the early 70's, and the border was wide open in those days.
A common price for many shoes was $12.99. You would ring up the $12.99, also manually add the tax (.65 in this case). Also common was having a customer pay with a $20 bill.
You would say, while handling the money: "That's $12.99 plus .65 cents tax for $13.64. Here is your change, (penney) 65, (dime) 75, (quarter) 14, (dollar) 15, and a five makes 20."
I don't even bother trying to make t easy for clerks these days, trying to give them pennies and such, since 99.44% of the time you are going to end up with the same hassle that began this thread. Sigh.