The plumber and his work were fine.
The price, not so much.
Cost of O Ring is 71 CENTS each. Cost to install on 3 toilets.. $345.
Let's review. Materials cost is a total of $2.13. Time spent doing repairs -1hr.
So I paid the plumber $342.87 for 1 hr of labor.
I believe that will help you when you call and they "can't give you an estimate over the phone".