Amazon offers the Greenies Petite Dental Chews 30-Count for $12.99. Add it to your cart via Subscribe & Save and in-cart it falls to $10.39 and bag free shipping. That's the lowest total price we could find by $8.
Of note, the Teenie 65-Count is available for the same price via Subscribe & Save.
Be sure to cancel Subscribe & Save after your order ships to avoid being billed for subsequent shipments.