i've charged $400 to change a few light bulbs without blinking.
that is the perfect question. telling the customer "that's the price the franchise set" is not the correct answer, either.
no...one of the down sides to actually learning your costs, and reflecting them in your pricing, is that you will inevitably lose customers who have used you when you were cheaper. Unless, you can now justify your higher pricing to them.
But in the example of the plumber, if you've been clearing a drain for this guy, every year, for 5 yrs for $150...then suddenly you become a franchise/Nexstar/Etc company, and realize you should be charging $300 for this service...how do you justify the additional cost for the same service to the same customer?