eBay with vipoutlet has the Member's Mark LED Floating / Hanging Speaker (PBB-300S) on sale for $25 - 10% off auto-applied in cart = $23 with free shipping. See reviews on Sam's Club. 

7 color options (flashes to music), connects via Bluetooth (2 paired max), 4-6 hours of battery per charge, can float in water or hung via metal hanger.