Meidong Acoustics via Amazon offers its Meidong Wireless Bluetooth Speaker for $34.99. Coupon code "77AS4QVA" drops it to $24.99. Plus, Prime members bag free shipping. (Non-members can spend $35 or more to qualify for free shipping; otherwise, shipping costs $7.12.) That's $25 off list and the lowest total price we could find. It features Bluetooth 4.0 and up to seven hours of playback.