They are desperate to get this thing out there:
http://www.v3.co.uk/...pgrade-windows-gbp25http://www.windowsit...ial-promotion-143592This seems to be any version of XP, Vista or 7 to 8 Pro and they are even throwing in Windows Media Center for free during the promotion (well whoopdidoo).
Seems you are going to be able to upgrade to Windows 8 Pro for $39.99 (US) or £25 (UK) until the end of January from the day of release.
That is for a download version. You can get a DVD but it will be $70 - (yep that's $30 for a DVD that costs 15 cents) (see articles)
Either they are trying to compete with MacOSX prices or they are desperate to tempt people to adopt early so they can say what a success it has been!
They are either being clever marketing it like this or the bad press rumbling over this release has them scared! Can't quite decide which. I suspect it is the first because they see Joe public adopting Metro wholesale and buying everything they need from the store - maybe that will happen - or maybe pigs will fly.