FREE Bag of Purina ONE Dog Food! January 8, 2019 by Tara Kuczykowski 2 Comments Pledge to take the Purina ONE 28-Day Challenge, and you’ll receive a coupon for a FREE bag of Purina ONE Dog Food by mail! LIMIT ONE PER INDIVIDUAL, HOUSEHOLD OR E-MAIL ADDRESS. Offers valid while supplies last. Good only in the USA, APOs, FPOs.