M40x Certified Refurbished on Amazon (Prime shipped):
https://www.amazon.com/dp/B016YKB8ZU
... or new/used:
https://www.amazon.com/gp/offer-listing/B00HVLUR54
EDIT: The price will likely be cheaper than offered here. Savings could be applied to purchasing leather earpads to replace the absolute crap (uncomfortable, shallow) M40x stock pads. I recommend the Brainwavz sheepskin pads (non-angled) which improve comfort and sound (more bass, less treble, better defined soundstage).