Yangdock E-commerce via Amazon offers the Lumsing 12-volt AC Adapter and Charger for Microsoft Surface Pro, model no. MS12258, for $26.99. Coupon code "BLACKY25" drops it to $20.78. With free shipping, that's $6 off list and the lowest total price we could find. It features a 5-foot cable, USB 3.0 port, and compatibility with Microsoft Surface Pro 3 and Pro 4 tablets. Deal ends November 28.