Windows 8 pricing details?

Like just about everyone else I'm tooooo excited about Windows 8. I just can't wait to update to the real deal from Release Preview. October 26 just can't come fast enough! One Surface too, please!

So, I was just looking up the pricing details for Win8 Pro and it says $40 for a digital download and $70 for the physical copy, at least at launch, following which they will rise again. That seemed like a weird deal, considering that DVDs are dirt cheap and massive software upheavals have been known to crash even the mightiest of server farms. But I didn't mind. Why would I, it's 40 damn bucks! The Obama 'Not Bad' meme immediately popped up into my mind, as I remembered the days when we had to cough up a couple of Benjamins for the a legit copy. And my chain of thoughts led me to think - Why the heck is what is possibly THE BIGGEST Windows overhaul so damn cheap?

That's when I had an epiphany - Nowhere has any website, blog or forum enlisted the number of licences included! Which brings me to my main question - how many licences will the download and DVDs encompass? (I believe that the download will have one while the DVD should have two, to justify the high(er) prices, but those are just my hopes).

[P.S.: Yes, I own just one computer and need to upgrade just that one, but it really isn't good enough for college, and the laptop that strikes me as the perfect one for college is the - brace yourselves, or rather I should - the Macbook Pro with a Retina Display. I know how much you guys, being the 'Microsoft Tribe' hate it, but that's a topic is for another discussion.'That device' will be one of the chosen few not to have Windows 8 bundled within it, and I really don't wanna pay a premium price to buy something I already own, hence the whole discussion.]

I just read that I need the System Builder edition to run Windows 8 on the rMBP, since it wouldn't be an upgrade, but a fresh purchase instead. But, if I were to install Windows 8 Release Preview on it first, wouldn't that make the full version, technically speaking, an 'upgrade'? That would enable me to install a version of Pro which I had bought as an upgrade, wouldn't it? Please correct me if I'm wrong.