Some scrap yards will buy the car batteries by the lb pound while others will give you a flat price for the car batteries.
One scrap yard in my area buys the batteries by the pound and gives like 3 cents per lbs or around $2.00 to $3.00 per battery depending on the weight of the car battery.
Another scrap yard buys the batteries for a flat fee for each battery and gives $5.00 per battery which is much more than the scrap yard gives you per lb.
So you can get between $2.00 to $5.00 per car battery depending on weight and size of the battery.