Gotta be mindful of purity in those instances. I’d rather source mine from reputable outlets. Course, it doesn’t hurt to have a fairly reliable source. Funny thing, you can still purchase it from south of the border due to their third world status. Go figure.
I suppose the upside is we’re rapidly approaching third world status so R12 should be available and affordable before too long.
I never had any problems with R12 bought on eBay. I’d look for recharge cans in good condition from high volume sellers. I don’t know where those guys went when eBay changed its rules. Around here the local sellers on Craigslist mostly just have a few cans for sale, but I guess if you can inspect them first it should be relatively low risk.