I preordered it, partly for the same reason as Onyx, so it is known some folks want it.
My experience with Amazon has been that they ship my items as they become available. For example, a few weeks ago I ordered both the Psycards set, which was out of stock at the moment, and the Pamela Coleman Smith Commemorative Set, which is not yet in stock. I received my Psycards yesterday, and the PCS set is scheduled for shipment May 8 (we shall see...
). I was only charged for the Psycards, not the PCS set, and I was not charged for shipping. I also ordered a Bohemian Gothic, which just shipped, and another deck a few months ago, and I have had the other deck for a few months now, again only charged for the items as they shipped, and not for postage. I have had many experiences like this with Amazon US.