I got $9 and change from the scrap metal dealer for a group size 78 car battery last year. That's twice what a battery place would have given me for it.
Batteries don't contain much lead; they have lead oxide and lead sulfate in them. It *can* be converted back to metallic lead, but not easily and not safely. Take the money and run.
"The only way to stop a bad guy with a gun is with a good guy with a gun"