Found a can of R-12 at home. Any value with it still?

I gave the 2 cans I had to a guy who restores vintage 'Coke' machines. So you may want to contact someone in your area who does that and see if they'll give you some $$ for it.

I know R-12 was also used in many, many Elkay water coolers, and those things last forever.

As far as autos go, I imagine most of those were converted over to R-134A, albeit at a loss of cooling capacity.

A single can is worth probably $25-40 depending on whether its a 12oz or 14oz.

Check ebay, and filter on the left by "Sold Items" to see what they are selling for.