$1/1 Robitussin Coupon + Walmart Deal March 15, 2012 This post may contain a link to an affiliate. See my disclosure policy for more information. Coupons.com has a great $1/1 Robitussin coupon available to print! The best thing is that there are no size restrictions, which means you can get the to go size for FREE at Walmart and CVS. Robitussin To Go (2 ct.), $1 $1/1 Robitussin Product Final cost: FREE!