When you buy a new car battery you can turn in your old car battery at the store you bought your new car battery and get a core charge fee back which can be around $10.00.
When you buy a new car battery they charge you a core charge and when you bring back your old car battery you're refunded that core charge.
You can also find some scrap yards that may give you $5.00 per car battery which is what I did to get rid of 5 car batteries that I found on the street before.
Out of those 5 car batteries I picked up on the street I got $5.00 per car battery which got me $25.00 which got me some gasoline for my car.