I have a 93 b2600i and I'm looking to get the a/c switched over to r134. Has anyone changed theirs over or know where I can get a kit without costing too much?

 

People I know have converted their Mazda trucks systems successfully to R134a. Note that the R-12 type "mineral" oil must be removed, not so easy.

I suspect that you have/had a leak of refrigerant, why you are considering changing. I'm in Arizona, installed a new compressor myself in my 1988 B2200 last October, stayed R-12. The higher cost of R-12 is offset by the simplicity of not changing over. If you haven't fixed your leak, then you're throwing your money away either way, as refrigerant is not a consumed item (I've got a '98 Frontier with 201K that's still on its original refrigerant).

 

I've talked with a guy i work with and he has all the equipment needed to evacuate, flush and test before adding r134. I should be able to save over $100 from having a shop do it, besides i don't know where to get r12 nor do i have the permit to get it.

 

One can buy R-12 on Ebay. Some vendors will require the certificate, about $25 online.

Just don't add anything with sealers or leak stop, you'll ruin the system. A little UV-dye is OK. That guy sounds like he knows what he's doing if he can flush the system. He may not do R-12 because he has little call for it so doesn't have the legally-required separate recovery/fill equipment.