Amazon offers the Duracell Coppertop AAA Battery 28-Pack for $11.70 via the directions below. With free shipping, that's $0.42/battery and the lowest total price we could find for this quantity by $11, although we saw it for a buck less in May. To get this deal:

1. Sign in to your Amazon account
2. view the Duracell Coppertop AAA Battery 28-Pack for $14.65
3. click "Clip this coupon" to take 75 cents off
4. add it to your cart via Subscribe & Save for $12.45 and free shipping
5. in-cart, it will fall to $11.70