Which wires you disconnect depends on where the problem is located--on the low-voltage or the high-voltage side. But just to be sure the 12V fuse(s) for the AC could be pulled, and the connector for the HV pulled, and that would disable it completely.
With the car OFF and key out of the ignition there will be no HV on the wires to the AC. The connector could be pulled and the junctions covered with electrical tape to keep out dirt and rainwater.
The AC compressor is so expensive because it has a small motor inverter built in, along with the 3-phase motor driving the pump--it is like a small version of our car without the gearbox, shafts and wheels.
i would be happy to troubleshoot and repair it for you.