I just found a decent price on a 91 4x4 yota. Does anyone know if 91 has r134 or r12. My 89 is r12, which works great, but I am dreading the day that I have to put new freon in...

 

All '93 and earlier models used R12 from the factory.
Any of these may have been converted to R134A over the last 20+ years.
If the conversion was done professionally, there should be a conversion label attached under the hood, and the correct type fittings for the new kind of refrigerant should have been left mounted to the service ports, so that the original type refrigerant can no longer be easily charged into the system.