The official price for a Windows 8 upgrade is $39.99, but if you have an existing system running Windows 7 you may be able to take advantage of Microsoft's $14.99 upgrade offer for recent purchasers of new computers. And if you're installing on an entirely new machine, a model Microsoft claims it doesn't support yet, you can still take advantage of the $69.99 "box copy" price rather than paying for a legally-dubious OEM copy. Here's how to do it.
Microsoft launched the upgrade scheme back in June, to ensure large numbers of people didn't put off purchasing machines ahead of Windows 8's official release last week. The Next Web notes that the online form for registering for an upgrade effectively works on an honour system; provided you say you purchased your machine after June 2, you can upgrade for $14.99.
Meanwhile, our own testing suggests that if you have installed the final version of the code but haven't got an official installation key, you can upgrade for $69.99, by using Microsoft's 'Get Genuine' route to acquire a product key. Kick off the process by selecting 'Activate Windows' in settings.
No telling when these loopholes might close; Microsoft wants to encourage rapid adoption of Windows 8 (and has apparently sold 4 million upgrades already), but it doesn't necessarily want to give the operating system away. If you're contemplating upgrading, take advantage while you can.