Tacklife via Amazon offers the Seedforce S100 Wireless Bluetooth Speaker in Grey for $18.99. Plus, Prime members bag free shipping. (Non-members can spend $49 or more to qualify for free shipping; otherwise, shipping costs $6.48.) That's the lowest total price we could find by $6. This portable speaker features a 5-watt driver, rechargeable battery with 16 hours of playback time, USB power cable, and 3.5mm audio cable.