Real Dogs. Real Differences. Purina ONE is asking dog lovers all over the country to switch to Purina ONE® SmartBlend® dry dog food and join the 28-Day Challenge. Thousands have shared the differences they saw in their dogs. Watch the video to see what the 28-Day Challenge is all about, then register your dog to receive a $3 coupon. What differences will you see? Register Today Learn More | coupons Save $1.50 on one (1) bag of Purina ONE® SmartBlend® Dry Dog Food, any size, any variety. Coupon effective dates: 3/27/2015 - 8/31/2015 Clip Coupon Save $1.00 on one (1) 3.5lb or larger bag of Purina ONE® Dry Cat Food, any variety. Coupon effective dates: 3/27/2015 - 8/31/2015 Clip Coupon |