It all depends on the market region.
I've attended meetings with CCS and water districts.. In my area $100 is unacceptable and way to high. A test can be done in just a few minutes if you are good at it.
Our minimum charge is $40 for a test.. $45 for people that have to meet us.. $75 for alarm activated devices that we must call the monitoring company and $75 for devices inside vaults under ground such as 8" devices. I deal with .5" devices often enough too..
This may be cheap to you? Then again our company alone concurrently tests over 5,000 devices a year.