Cambridge Soundworks via Amazon offers Prime members its Cambridge SoundWorks OontZ Angle 3 Ultra Portable Bluetooth Speaker for $19.99 with free shipping. That's $1 under our June mention and the lowest price we've seen. (It's the best deal today by $2.) It features a 100-foot wireless range, built-in mic, and 20 hours of playtime.

Update: The price has increased to $24.99. Clip the on-page $5 off coupon to drop it to $19.99.