If you take your car to a shop one way or another, you will end up paying the said ammount. Granted circumstances may arrise, but 9 times out of 10 you will pay what price is given after said service is done. Shops are a business, and nothing is free, if that were true Goodwill would open up a shop.
I'm not always believe 100% of anything anyone tells me, but like a butcher, I'll take his word for it rather than sticking my head up a cow's ass. If most shops weren't in anyway shape or form professional, they won't last.