Ebay offers Ecoxgear Floating Bluetooth Speaker and Dry Storage for $28 (reg $70) with free shipping.

Product Description:
100% WATERPROOF AND DUSTPROOF - meets IP67 international standards, no worries with rain, sand, or snow; Drop it in your pool, lake, or ocean - no worries, it floats

• DRY STORAGE - a large, spacious, watertight dry storage for your phone, keys, and more; External music and phone buttons enable full control while your devices are safely stored inside
• BATTERY LASTS FOR HOURS - up to 15 hours of playtime at average listening levels, 5 hours at max volume; Battery fully re-charges in approximately 3 hours; Speaker plays while the speaker is recharging
• BLUETOOTH V5.0 - streams audio wirelessly from your device while inside or use it as a standalone speaker and stream audio from a Bluetooth enabled device up to 100 feet away