The JBL Flip 4 waterproof wireless speaker is a great deal at $60 (Update: Expired) - CNET
JBL FLIP 4 - Waterproof Portable Bluetooth Party Speaker - Mo & Joe Electronics
Speaker Carrying Travel Protective Case For Jbl Flip 4 Wireless Bluetooth Speaker Shockproof Waterproof Hard Shell Case - Earphone Accessories - AliExpress