All4Cellular offers the Plantronics Push To Talk Headset with Boom Mic in Black, model no. MX256-X1, for $3.49. Coupon code "A4C20" cuts it to $2.79. With free shipping, that's pennies under our mention from three weeks ago and the lowest total price we could find by $3. These headphones feature a simple answer/end button and noise-cancelling microphone; they're compatible with all phones with a 2.5mm or 3.5mm plug via an included adapter.