Mwave offers the Bravo View Kid-Friendly Automotive IR Wireless Headphones, model no. IH-04A, for $19.99 with free shipping. That's the lowest total price we could find by $4, outside of the mentions below. These headphones are recommended for ages three and up and feature a multi-level adjustable headband, auto mute, auto power off, 30mm mylar speakers, and wireless range of up to eight meters.
A close price: Walmart has them for $21 with in-store pickup, while Amazon charges $21 with free shipping for Prime members.