Free Sample of Dunkin Donuts Frozen Coffee This post may contain affiliate links. Please see dislcosure policy. May 19, 2017May 18, 2017 by Daphne Murray Head over to your local Dunkin Donuts from 10AM to 2PM today, May 19th and get a FREE sample of their brand new frozen coffee! No purchase or coupon required. Valid while supplies last. Thanks, Freebie Shark!