Amazon offers its Prime members the Plantronics M50 Bluetooth Headset for $19.99 with free shipping. (Non-members can spend $35 or more to qualify for free shipping; otherwise, shipping costs $6.25.) That's tied with our mention from Black Friday last year as the lowest total price we've seen for this headset. (It's also a current low by $16.) It features up to 11 hours of talk time or 16 days of standby time. Deal ends December 1.