Currently you can sign up for the Science Diet 3 bag challenge and get a 5.00 off coupon. Go to the link below for the scoop on that. After doing so, if you have Petco near by they have Science Diet 35lb bags or larger for 8.00 off this week. Combine this offer with the 5.00 and 2.00 off(survey coup if you have it) and you can save 15.00 off a 35lb bag of dog food! Use your Petco P.A.L.S card and it will count towards one of your ten bags of food.
If you are weary of changing your dogs food, the 5.00 off coupon is good for any 4lb bag or larger. I'm not sure of the exact pricing but most 4-5lb bags of Science Diet run around 10.00. Combine the two coups above and get a small bag for around 2-3 dollars and donate it to a local humane society or rescue group!