Right now the Twilight manga graphic novel is being offered by Amazon.com at 55% off cover price
Which is basically the same price shops will pay for it.
So, for retailers, this could be a very attractive way to stock up on copies in case traditional routes run dry, for when the book is released.
For readers it's a way to get a bargain now – and maybe even cancel if your shop gets a copy in first.
And for speculators – well, it's not like this is X-Men: Nation X, a hardcover that may go shortly out of print after release. But since you're getting the same deal booksellers are, you might be able to make something on it.
And you know what? At that price, even I might try it. It might be even cheaper for me that way, the UK price is still only 10% off.