If someone does not own the tools (can you say Torx TX-25?) and has the mechanical ability of a turnip, a Haynes or an other manual will not help.
OTOH, if the installation is done gratis, then you get to cut out many of these steps, and most of the remaining steps are done anyway to complete the sale of the part. What this job really takes is “Hey Ralph, grab a screwdriver and put this visor in for Mr. P” instead of running it through the system like a big job.
If Joey gets a survey call, he should definitely mention that $50 seemed out of line for a job he could do himself in under 5 minutes, including time to open the box and scrounge through the kitchen drawer for a screwdriver.
I also feel a little bit angry with the shop, thinking about that person who isn’t mechanically capable. The person who is too scared of damaging something to do a simple job like this gets completely screwed because they can’t just walk away.
The funny thing is I’ll bet either of my regular mechanics would have done the job for free, even if I didn’t buy the part from them just becuase I’m a worthwhile customer to them.