At the start of this year, it was practically impossible to find the Sony WH-1000XM3 for less than MSRP. Since then, discounts have gradually become more and more common, though this latest deal is probably the best we've seen yet. A seller on eBay is offering manufacturer refurbished units for just $199.99 a pop, well under any previous deals we've seen.
Having reviewed the 1000XM3, I can attest to how solid a pair of headphones it is. It's virtually faultless; the sound is clean and clear, the noise cancellation blocks out practically everything, and the battery life is longer than that of any plane ride. It doesn't hurt that it recharges via USB Type-C, helping eliminate the need to bring a bunch of cables with you when you travel.
The eBay seller, secondipity, seems to be relatively trustworthy with 98.6% positive feedback and 48,905 stars. These are manufacturer refurbs, meaning that they've been looked over by either Sony or an approved refurbisher. They may have light scratches and may not come in original packaging, but a 90-day limited warranty and 30-day returns are noted in the listing if you have any issues. Free shipping is also included. Both black and silver colors are available, but you'd better hurry; eBay is showing its dreaded "Limited quantity available" indicator.