I should have added in my original comment that she had asked in advance if a copay would be needed, but they couldn't answer her question, telling her that they wouldn't know "until we run it."
I often got the same answer about my dad's health care and his medications. Often, not even the people providing the services can tell patients in advance what the services will cost.
I guess to a lot of people, $75 is trivial, but to an elderly woman living on social security, $75 can be a big deal if it has to last till the end of the month.