Ailihen via Amazon offers its Ailihen Kids' Volume Limiting Headphones in several colors (Turquoise pictured) for $19.98. Coupon code "VK74KYDY" drops it to $11.99. Plus, Prime members bag free shipping. That's $8 off list and the lowest price we could find. They feature a microphone, SharePort (so you can connect other headsets), and a volume limit of 93 dB.