If you have previously purchased a 12pk of Dr. Pepper, there is a chance that, inside the box, you received a coupon for $1/1 12pk of Dr. Pepper, in which case you could pay just $1.50 for a 12pk or just $0.13 per can!!!
Another offer for this deal I just came across is that Ibotta currently has an offer to earn $.50 wyb any 1 12pk of 12oz cans of soda.
So whether you have the coupon or not, you could still earn savings if you have the Ibotta app on your smartphone.
Have the store's coupon policy on hand.