Thousandshores Inc. via Amazon offers the Dr. Meter Kids' Noise Blocking Protective Ear Muffs, model no. EM100, for $12.99. Coupon code "JP37PRC7" drops them to $9.99. Plus, Prime members bag free shipping. (Non-members can spend $35 to bag free shipping; otherwise, it adds $6.87.) That's $3 off and the best deal we could find. They feature a 27NRR noise reduction rating.