Amazon offers Prime members the SteelSeries Siberia X100 Gaming Headset in Black for $19.70 with free shipping. (Non-members can spend $49 or more to qualify for free shipping; otherwise, shipping costs $4.98.) That's the lowest total price we could find by $40. It features an Xbox Live chat adapter, integrated microphone, and a 3.5mm plug.

Note that it's temporarily out of stock but still available to purchase at this price for delivery when available.