Get a FREE bag (3.5, 4, or 6-lb) of By Nature dog or cat food after rebate (up to $12.99 value). Just fill out the form to receive a link via email to print your mail-in rebate form. This offer is valid August 10 through November 10. You will need your UPC and original store cash register receipt to send in with your rebate form. The deadline to mail in your rebate is December 31, 2010.