Tensun via Amazon offers its Tensun International Travel Plug Adapter with 2 USB Charging Ports in Black for $15.99. Coupon code "8TJXMQ53" cuts that to $11.95. Plus, Prime members bag free shipping. That's $31 off and the lowest price we could find. It features four built-in plug standards (US/EU/AU/UK), a detachable standalone charger with two USB charging ports (two with smart charging), and a slide-out plug release button.