With purchases of $25 or more, Amazon offers the Wellness Core Natural Grain Free Dry Cat Food 2-lb. Bag in Original Turkey & Chicken for $6.07 with free shipping. (Non-members can spend $35 or more to qualify for free shipping.) That's $8 less than picking it up from your local pet store.
Note that this item is sold as part of Amazon's "Add-on program" and can only be purchased with an order of $25 or more. Also, this item will ship in 1 to 2 months.