What should replacing the innards of a toilet cost--ie fixing a toilet?

OK I’ll take a stab at it. I will assume this is a commercial handyman and not a guy in the neighborhood with a tool box.
The highest cost will be the service call and the time to get to your house, billing, scheduling, staff, insurance, truck, supplies on hand, etc.
Call that $200 and includes 30 minutes of actual work.

You didn’t say what he fixed. If it was the leaking stopper +$10 with markup 210 +tax = $225
If the valve assembly was replaced: +50 with mark up 250 + tax= 267.50
If something broke along the way, e.g. corroded pipe, add extra $90/hr.

How’d I do?.

They sell kits for that at any hardware store for under $20.

What you’re paying for is his time, travel and specific knowledge of how to install the pieces of said kit. Which is why plumbers make the money they do.

So…. how much was it? I can’t stand the suspense. PM if you don’t want to say publicly