There is probably no answer to your problem as changing a timing belt is hardly a D.I.Y. sort of job. I suppose you must consider if it is worth you spending so much on the car. How old is the car, how long do you intend to keep it, how much of a risk are you willing to take. etc. Even if you shop around you may not get a better price and anyone who was willing to do such a job cheaply would be rather suspishus and probably unreliable. My Ford Fiesta is now 11 years old and there is no way that I am going to spend that sort of money on it.