Thumb Score: +24

Amazon [amazon.com] has 12-Pk 12-Oz Dr Pepper Soda 3 for $18 – $2.91 (multibuy discount) – 5% when you check out via Subscribe & Save = $14.19.
Shipping is free with Prime or on $35+ orders.

Target [target.com] has for Target Circle Members (free to join [target.com]): 12-Pack 12-Oz Dr Pepper Soda at 3 for $25.17 – $10.07 (Buy 3, save 40% discount) = $15.10. Select free store pickup where available.