ac won't work

Your car originally came equipped with a refrigerant called R12 which is no longer produced and if it is found is quite expensive. Your air conditioning system may have all ready been converted to the more modern refrigerant R134a. If the compressor turns on but does ot cool well the air conditioning system must have a leak which needs to be found and repaired prior to just replacing the refrigerant and having it leak out again.

you might have coolant but no power to the compressor Could be a problem with the climate control box or AC relay clutch.