Best thing to do is call a few shops and have them work up
and estimate over the phone, or let them do the estimate
and call you back. Then, ask them what the hours are for
doing the job.
After getting this info from numerous shops and comparing
what they've come up with, you'll have a pretty good idea
about this.
Be sure and have them retro fit your vehicle with R134Freon
if it didn't come with this from the factory. If it originally came
with R12, you don't want to put that back in the car since
R12 is almost impossible to get now, and if you could get it
it would probably cost about $1,598,456.23 per pound!