If you're in the market for a budget-friendly device that follows where you go, check out Kunodi's Outdoor Waterproof Bluetooth Speaker ($17). For a lower price than the Bose wearable device, you can clip this speaker onto your lanyard, water bottle, clothing, or keys and move freely.
This shockproof, dustproof, and waterproof sound system can even project your playlist during a post-sweat shower, too.