If the business tells the customer the price up front and the customer agrees to the price and after the work is done satisfactorily, the customer is charged exactly the price they were quoted, the only person to blame if they are not happy with the cost of the job is the customer.

Some services can't have a price quoted immediately due to the nature of the work, but once the price is quoted, I expect the business to honor the price just as the business expects me to pay the bill.

And BP, your prices were too low for the quality of the work you did.