I have always serviced my own cars, 200-250 is about right for a main dealer. oil and filters shouldnt come to more than 40-50 if your willing to do it yourself however.
It's a book that comes with your car - every time it's serviced it gets a stamp to show a continuous history of being looked after according to the service schedule laid down by the manufacturer. If you buy a car with FSH then it's this that gives you that proof.
Thanks Krikkit. what I meant to ask was, would the local mechanic be able to stamp the service book and give it the same credibility as if the service was done by a ford dealership and the service book stamped there? To date, I have a FSH
He will stamp it, and it will still have a FSH, but if you wanted to be really picky a dealer/specialist stamp is more worthwhile than a random garage stamp. For servicing I don't think it really makes much difference, as long as they do follow the recommended service items and put the right oil in (worth checking that they will if taking to an independent, often they just buy barrels of 5w40 or 10w50 and use that on every car).
Any garage can service your car, and the stamp is as legal as any dealer stamp, as long as they follow the guidelines set out by the car manufacturer. Look into the Block Exemption law.