Purina offers a bag of its Purina One Dog Food for free when you fill out a short form. (You'll receive a coupon for a free bag via mail; it'll arrive in two to four weeks.) Although we saw it one month ago, that remains a rare offer for a free bag from Purina. (Most offers are for free sample pouches.)

For our feline friends, Purina also offers a bag of its Purina One Cat Food for free after filling out a short form.