With orders of $25 or more, Amazon offers the Pet Qwerks Flavorit Large Nylon BarkBone in Peanut Butter Flavor Infused for $3.74 with free shipping. That's the lowest price we could find by $5. It's infused with human-grade peanut butter flavoring that is allergen-free.

Note: This item is part of Amazon's "add-on program" and can only be purchased with orders of $25 or more.