Agree with greg. I know NAPA has the bypass pulley, so other stores should also! About 45.00 retail. Compare prices with used compressor, about the same amount of labor either way! One advantage of a GOOD used compressor is, that much of the repair would already be done 'IF' you decide to fix the system later! However IF you do not plan to fix it then the bypass pulley is probably the way to go. Keeping in mind that just replacing the compressor is not all that is needed for the complete repair!
some veh they make an aftermarket idle pulley and bracket for. call your parts house and see if they make one for your car. you cat always buy a used one and just not charge it so it acts like an idler