Amazon offers Prime members the Kinivo ZX100 Mini Portable Speaker in nine colors (Black pictured) for $15.49 with free shipping. (Non-members can spend $35 to qualify for free shipping; otherwise, it adds $5.14.) That's the lowest total price we could find by $7, although we saw it for $3 less last month. This portable speaker features an Expansive Resonator Construction Design, 3.5mm audio socket, 360-degree sound, and travel case.