Amazon offers the Greenies Original Regular Size Dog Dental Chews 36-Count Pack for $20.90. Checkout via Subscribe & Save to cut that to $19.86 and bag free shipping. That's the lowest price we could find by $4.

Note: Be sure to cancel Subscribe & Save after your item ships to avoid being billed for future shipments.

Update: Clip the 15% off coupon on the page to yield a price of $16.71.