Tensun via Amazon offers its Tensun International Travel Plug Adapter with 4 USB Charging Ports in Blue for $17.99. Coupon code "5ZEWHHKA" drops it to $12.45. Plus, Prime members receive free shipping. That's a buck under last month's mention and the lowest price we could find by $9. It features four built-in plug standards (US/EU/AU/UK), four USB charging ports (two with smart charging), and a slide-out plug release button. Deal ends April 30.