Amazon offers its AmazonBasics AAA Alkaline Battery 20-Pack, model no. LR03-20P, for $5.74. Add it to your cart via Subscribe & Save to knock it to $5.45 and bag free shipping ($0.27/battery). That's a buck under the lowest total price we could find for 20 similar batteries shipped elsewhere, although we saw these for $2 less in March.

Be sure to cancel Subscribe & Save once your order ships or you'll be billed for subsequent shipments.