Today only, MidnightBox.com offers the refurbished Rocketfish Mobile Bluetooth Headset, model no. RF-QX3, for $4.95. With $3.99 for shipping, that's $2 under our March mention and the lowest total price we could find by $6. It features up to eight hours of talk time, 160 hours of standby, and more.
Note that a 30-day warranty applies, but it's unclear who backs it.