Got my Silver AirPods Max from Amazon. (Ordered them on Saturday and they arrived today, Tuesday). They were $447 (Used-Very good; "minor cosmetic imperfection"). The Apple box had been resealed but the headphones and case had their wrapping and the headphones themselves are absolutely pristine.
When I bought them from Amazon I also purchased AppleCare. But Amazon emailed me to say no AppleCare unless the device is sold by Amazon (these were Amazon Services).
Checking online, they came up as "not eligible" for AppleCare and I had to call Apple Support. But I now have AppleCare on them. (I don't need any more stress in my life).
Just the little bit I've listened, they are wonderful. You can imagine what an upgrade these are from my AirPods!