This deal has ended.
Buy.com has the Plantronics Explorer 340 Bluetooth Headset for $36.24 (an additional Plantronics MX100 Mobile Headset is also included). Shipping is free and there is no sales tax (except CA, MA, MD, TN). It features up to eight hours of talk time and 33-foot range. The next best deal on the headset is Newegg $30.99 with $6.99 shipping, and that doesn't include the additional headset.