Amazon has this Boombotix Boombot Bass Station Bluetooth Speaker with 15-watt Subwoofer Dock on sale for $29.99. It features a 2GB flash drive for music storage, Siri and Google Voice controls, water resistance up to 3 feet, dual-amp stereo sound, and a 15-watt subwoofer dock that also acts as a charging station. Shipping is free on orders of $49 or more.