Price out two calipers, pads, rotors, 20-40% markup from cost on those parts then add in 1.6 for the pad/rotor change plus 1-2 for the caliper replacement.
Mitchell time manual if you want to be picky.
I'm willing to bet its over $400.
As for the terrible brakes, its possible they explained the "solution" could cost more and the customer ( GF's mother) said no just the bare minimum.
MOAR DETAILS PLZ.
Because without them, this story is about as useless as a GP in the autocross...