Amazon has 2-Pack 1-L Listerine Antiseptic Mouthwash (Cool Mint) for $11.98 – 5% off when you checkout via Subscribe & Save – 20% off when you clip the coupon on product page = $8.98. Shipping is free w/ Prime or on orders $25 or $35+ orders (minimum requirement varies by location).
Note: Coupons are usually limited to one per account. If you’ve already used 20% off coupon for Listerine before, you may not see a coupon this time.