It really depends on what is going on with the sax - a chem clean requires a total rebuild - it goes into a liquid. If there are dents and springs and swedging to deal with, it could be a lot. I would say around 400 bucks starting out for a rebuild with student grade materials - get into the pro level horns and those start at around 600. If the sax is really dirty, it could eb very worth it - weh have ahd trumpets come in so corroded (cough...yamaha.) that they would hardly play, chemical clean them, work on the valves, and they play alright - a sax wont reap as great effects - unless the thing is friken filthy with grime all up the body tube and in the neck and probably some on the outside.