If it is a 5 series, it might worth...
http://www.bimmerfest.com has lots of diy fix, which might saves you tons of money.
I did follow what the forum threads said to replace all brake pads/rotors for my 325i (couple of years ago) at about $180, and my local dealer quoted $1100 plus tax for the very same job. My point is the repair cost depends,
good luck