Amazon offers the Blue Buffalo Life Protection Formula Adult 30-lb. Dry Dog Food Bag for $45.99. Clip the on-page coupon code and checkout via Subscribe & Save to cuts the price to $34.49. With free shipping, that's the lowest price we could find by $12.

Note: be sure to cancel the subscription to avoid being billed for subsequent shipments.

Update: The price now drops to $36.79 at checkout.