Newegg offers the open-box Plantronics GameCom 780 USB Gaming Headset, model no. 86051-4, for $24.99 with free shipping. That's $15 under the lowest total price we could find for a new model. It features a noise-cancelling mic, 7.1 surround sound, USB, and on-ear controls.
A 1-year limited warranty is included, although it's unclear who backs it.
Note: This product is new but may not be delivered in its original packaging and does not come with the manufacturer's software.