Dunkin Donuts: FREE Cold Brew Coffee Sample Pack! This post contains affiliate links which means that we may be compensated if you click a link and make a purchase.. May 9, 2018 by Karen-Kupon Girl Leave a Comment Dunkin Donuts offer Sign up today to receive a free trial sample of our Dunkin’ Donuts Cold Brew Coffee Sample Pack. Offer valid through May 17, 2018, while supplies last. Read more HERE Get A Grocery Budget List + Pantry Checklist Printable When you Subscribe to Kupon Girl!"We Respect Your Email Privacy"