It’s one thing to buy a $10 headphone without worrying too much about authorized dealer status, but when you are going to put down two orders of magnitude that amount, authorized dealer status is definitely a much bigger factor. So if while price checking around you run into the Sennheiser HD800 going (in new condition) for $1000 at Amazon.com, note that the sellers having them for $1000 are not authorized or recognizable A/V sellers. Amazon’s own price is $1400 and if you price-check around that’s the price at other well-known sellers like B&H, Sweetwater, WWS, Crutchfield, etc.
PS: note also that Jet.com does NOT reveal who the seller of an item is, so you have no clue who you are buying it from, so you cannot know of warranty status ahead of purchase. Again, not a big deal with a $10 item, but for something like this, it is very important.
UPDATE 5/30/16
Thanks to Allan for pointing this in the comments!
You can also get it refurbished for $1000 from Crutchfield with a 2-year warranty and 60-day money-back guarantee.
If you are not a perfectionist, Crutchfield also has a scratch and dent refurbished for $850. This is marked as low stock.
Crutch field has factory refurbished with 2 year warranty for $999
thanks Allan! I just updated the post! It looks like they also have a “scratch and dent” refurbished for $850.