Amazon has 20-Pack AmazonBasics Alkaline Batteries (AAA) on sale as listed below when you ‘clip’ the 30% off coupon on the product page and checkout via Subscribe & Save.
Note, must be logged in to clip coupons; coupons are typically limited to one per account. You may cancel Subscribe & Save anytime after your order ships. Select the later date from the "First Delivery On" menu to get traditional S&S checkout instead of adding to your cart.
https://www.amazon.com/gp/product/B00NTCHCU2