Walgreens: FREE Purina One Dog or Cat Food May 25, 2011 by Mitchell Wischmann This post may contain a link to an affiliate. See my disclosure policy for more information. This past Sunday’s SmartSource insert included a coupon for $2 off Purina One dog or cat food. These are priced $1.99 at Walgreens, so FREE after coupon: Purina One Dog or Cat Food, $1.99 Use the $2/1 coupon from the 5/22 SS Final cost: FREE! The cashier will need to adjust the coupon down by a penny. Thanks, Wild for Wags!