eCase via Amazon offers the Kmashi 3-in-1 Bike Headlight / 4,800mAh Power Bank / Bluetooth Speaker
, model no. Arma K1, for $26.99. Coupon code "7WFFI67M" cuts that to $17.99
. Plus, Prime members bag free shipping
. (Non-members can spend $49 or more to qualify for free shipping; otherwise, shipping costs $6.91.) That's $32 off and the lowest total price we could find. It lights up to 164 feet and features a Bluetooth range of up to 33 feet, built-in mic, waterproof design, and bike mount.