In Qld, I took my son to the local Dental School(Uni) and it cost about $3500 all up. Quoted about $10k as had Overbite,underbite, teeth that had to have chains attached to be 'pulled' down.
The instructors supervise everything and they are dentists training to be orthodontists. They get to say they will take your child depending on tecniques they are teaching. No cost for initial consultations (and maybe free xrays and opinion - I can't remember). Appointments are set only for a couple of days a week as it is to fit in with Uni timetables.