i have been in that situation many times but oncommercial jobs where nthe situation is very different, however the customer is ususlly on some sort of time scale problem and expects to pay a premium, however it's usually 3 or 4 times the usual price... 'for fitting them in'as the customer had asked me for a house rewire estimate but had someone else rewire it.
When I mentioned this I got the "Oh they were cheaper" and then I asked why they did not get them to troubleshoot it they replied "We tried several but they never got back to us and we know that you are more reliable" Well no thanks not on that occasion I would not be thank you very much.
Sadly it is by no means the only time that I have been asked to repair a cheaper competitor`s absolute cock up. Cheeky gits!
I have never set out to be the cheapest or the dearest. I give what I consider a fair price both to myself and my customer. I would never engage in a race to the bottom or pile it on if I think a customer might accept it.
You need to learn that one