Ocean Technology via Amazon offers Prime members the Unitek Detachable 4-Port USB Charging Station Dock, model no. Y-2187A, for $29.99. Coupon code "6FDYVRAW" drops it to $19.79. Plus, Prime members bag free shipping. (Non-members can spend $49 or more to qualify for free shipping; otherwise, shipping costs $7.15.) That's $10 under our mention from a month ago and the lowest price we've seen. (It's the best today by $10.) It charges up to four devices at once, and is compatible with iOS or Android devices. Deal ends November 20.