97 cavalier AC COMPRESSOR PULLEY SYSTEM???

My friend took her 97 cavalier to a mechanic having problems with her ac and something to do with the drive belt. He told her she needed a complete AC compressor pulley system $600. Is it possible to pull one out at a junkyard and do it myself with the repair manual. If so, what parts would I need to pull out of a junk car to be able to have the AC compressor pulley system? Any advise or suggestions as to where to look or how to go about fixing this problem myself would be very appreciated.

Thank you for your time

c

Some metric sockets and wrenches and some time.The compresser clutch is what usually goes and the only fix is another compresser.It's a bitch to pull one out though.