The hardest part of quoting a job is to give the price to the customer. If you quote them honestly and fairly, your price should be competitive with others. Let it stand. If you don't get the job, you don't want it. I'm not going to work and not make any money, I can do that from the house. Show up on time, do what you say you will do, be professional, charge reasonably, you'll get all the work you need.
