I don't want to disapoint you but most cels
on eBay were bought outside of Japan or from
internet shops.

For that matter, quite a lot of cels sold on
Yahoo Japan are bought at shop like Mandarake
for much cheaper than what they are sold.

So what ? What's so special about that guy ?
At least, he sell cels that most people couldn't
have got themselve. Can't say that from
everybody.