Amazon offers the Duracell Coppertop D Battery 8-Pack for $7.74 with free shipping via the directions below. That's tied with our August mention and the lowest total price we could find by $3. These batteries claim to be mercury-free. To get this deal:

1. View the Duracell Coppertop D Battery 8-Pack for $9.99
2. click the "Clip this coupon" button for 75 cents off
3. add it to your cart via Subscribe & Save for $8.49
4. during checkout, it falls to $7.74