Ebay offers Altec Lansing HydraOrbit Bluetooth Speaker 2-Pack for $19 (reg $59.88) with free shipping.

Product Description:
The HydraOrbit EverythingProof Wireless Speaker is super portable and gives you big sound - anywhere. Loaded with up to 10 hours of battery life, this speaker will last through your longest hikes or beach days. With a certified IP67 waterproof rating, the HydraMOrbit can handle being brought onto the sand, mud or even tossed into the pool it will float. A carrying strap allows the speaker to be clipped or hung from your backpack, duffle bag, or outdoor awning. Pair two HydraOrbits together via True Wireless Pairing for double the sound.