Ending today, ATC LLC via Amazon offers the Lumsing Series 21-watt 4-Port USB Wall Charger in Orange, model no. 206-1015-1004, Grey, model no. 206-1015-1002, or Blue, model no. 206-1015-1003, for $12.99. Coupon code "7QVESANZ" cuts it to $8.99. Plus, Prime members receive free shipping. (Non-members can spend $35 or more to qualify for free shipping; otherwise, shipping costs $6.22.) That's the lowest total price we could find by $4. It purports to detect and automatically switch to the right charging mode of the connected digital device for full speed charging of up to 4.2 overall amps.