I got charged 5 hours. Well worth it to have it done by a licenced mechanic, for insurance reasons.
Be sure to get the ebrake cable with this. Best is to get as much of the rear brake/hub/knuckle/ebrake assembly as you can off a wreck in one go, not piecemeal.
It's worth it if you put in ss lines and upgraded pads - better choice of pads in disc than drum.