Keeps the price real by asking the guy what they actually do, but I don't buy that a shop like that is only wiping chains. A $40 tune at a big box is probably a real tune for the kind of rider who walks in there, and a lot of people just need their shifting fixed so it stops skipping. The gap between $40 and whatever you charge is mostly about how deep you go and the time it takes, not whether the other guy is a hack. Explain what the extra money buys and let the work speak for itself instead of laughing at the quote.

How many times did you dig through the bag before it clicked that the bag was the problem? I did the same thing last summer after a job where I was on my knees in a crawlspace hunting for a coax crimper. Dumped out nine tools that night, kept my good compression one and a stripper, and never looked back. The only thing I regret is not doing it years sooner.