I just rebuilt the front axle on mine and replaced the brake calipers ($120 pair) Rotors, ($98 a pair) and 100 series pads ($35). Factor in brake fluid you are at about $275 just in parts if you are rebuilding them with non-oem parts.
Since they do not seem to be replacing the rotors (as you did not indicate that they are) nor did you say they are rebuilding your calipers the price seems high to me. I also believe that some of these facilities can turn the rotors while still on the vehicle which obviously saves them a bucket load of time.
I also have a expedition that started to grind the front rotors when I was on a long trip with the family. I was tempted to sit down in the parking lot and replace the rotor and brakes there but my wife scolded me telling me we were on vacation and you are not working on the truck. Took it to the brake place where he tells me it will be $700 to do the work. Not only did the rotors need to be replaced but the brake cylinders needed rebuilding. I told him no, to just throw pads on it and I will take care of it when I get back to AZ. (I know not a good practice). He refused until I told him to back it out of the garage I would do it myself. He finally relented (still charged 150 bucks) but said he would not warranty the work and I wouldn't make it 100 miles. Long story short, I finally replaced the rotors and brakes, the calipers didn't need to be rebuilt, two years latter. (again I know not a good idea).
The long and short of it, do it yourself, do it right, save a heap of money, and take the Mrs. out to a nice dinner on the brake place and still have money in your pocket!