ThePruneDanish via eBay offers the Polaroid 50-watt Wireless Bluetooth Portable Stereo Amplifier Speaker in four colors (Blue pictured), model no. PBT3003, for $31.99 with free shipping. That's the lowest total price we could find by $16. This 7.35-lb. speaker features on-board controls, Bluetooth, a 3.5mm auxiliary port, and carry strap.
Want a pair? Add two speakers to your cart for $59.18 with free shipping ($29.59 each.) That's the best deal we could find for the quantity by $36.