He's free to do what he likes with his Amiga. If someone wants to throw $700+ at him for it then that's their lookout. Shame it was not offered to the community first but then if money is your motivator, you can't blame someone for going to Ebay. Get a couple of shills to help and you can easily rake in some serious cash.
Personally, for the future I'd suggest people think twice about offering any help/items for free/cheap to someone if all you end up doing is helping someone make a large profit at the expense of the Amiga community.
Now in true Criswell fashion I predict the following forum post in 1 week: "Hey everyone, I just got an 4000T and can't get it to recognize the large hard drive. Please help!"