As long as it still works and makes noise, it can't be the whole compressor just the bearing i guess.....still it would require dis-assy of compressor with gas recharging lets say 2500-3000.
Lets assume it is the compressor piston which is giving noise....either it would be a sanden or denso compressor in your car and some models are repairable.....
final resort is to get a kabli unrepaired compressor i think it would not cost more than 5000
get hold of an honest ac mechanic