FREE Bag of Purina One Dog or Cat Food!! This post may contain affiliate links or sponsored content. See Disclosure Policy. Freebies Calling all pet owners! Right now you can grab a FREE bag of Purina One Dog Food or Cat Food! Just take the 28-Day Challenge and fill out a short form! Your coupon will be sent via US mail and should arrive within 2-4 weeks and there is a limit of one per household.