Groupon is offering up 100% Cash Back on Your Dunkin' Donuts Purchase (up to $3). Also, receive 20% cash back on every additional visit for 2 weeks. Simply click on the ''Claim Offer'' button and add your credit card information. Then use that same credit card to pay for your purchase at Dunkin' Donuts. You will receive your cash back on your credit card statement within a few days. This deal is valid 14 days once you claim the offer.