If your shoulder is damaged a brake isn't going to help much. A lot depends on what is damaged and how badly. A torn tendon, for example, take roughly a year to go away, mostly. Mine still hurts a bit, but I have the use of my arm back.
Anyway, Epp's charges $100 plus the cost of the brake. Locally it should be around there.
Like guntech says, decide what brake you want first.