You know, it may be as you describe; I've never bought a package, I've just seen them displayed on embarkation day outside the dining rooms and Horizon Court. I just assumed they came pre-packaged; but maybe you can assemble your own.
As for being available online, I've never seen them, but then I've never looked for them either. In fact now that I think about it, I have been absolutely no use to you at all. So sorry.