13deals.com offers the Sergeant's Buddy's Glow Ball Jr. for Small to Medium Dogs for $4.99 plus 99 cents for shipping. That's the lowest total price we could find by a buck, outside of the price below. This non-toxic ball measures 2.5" in diameter and glows in the dark. Deal ends March 20.
A close price: Amazon charges $6.49 with free shipping for its Prime members.