Note, the SteelSeries Xbox One Headset Adapter will be included in this deal for free. To add it to your cart, once you click "Buy Now" on the product page, click "Add Xbox One Adapter" and then click "Add to Cart." Discount will be reflected at checkout.
Editor's Notes & Price Research
Our research indicates that the SteelSeries Siberia 800 Wireless Gaming Headset is $67.50 less (25.75% savings) than the next best price from a reputable merchant with prices starting from $263.
Once you've added to cart you can add the Xbox adapter (usually $30) for free.
At checkout, enter promo code steelseries15 for 15% off.
Sorry if this is unhelpful, but it's the first deal I've posted and doesn't look like the "internet" knows about this price yet.