Aropey via Amazon offers Prime members the Aropey 4-Port USB Charger for $15.99. Coupon code "CGSPFMLP" cuts it to $9.59. With free shipping, that's $16 off and the lowest price we could find. It features a charge speed of 2.1 amps, maximum charge speed of 4 amps, and a 4-foot power cord.