Until the 31st January you can grab yourself a copy of Windows 8 Pro for just £24.99.

As long as you have a legal copy of Windows XP, Vista or Windows 7 you can use this upgrade.

Go Here to get started.

You can use a product code from an old laptop or Windows install CD. Most people have at least one from an old laptop. Even if you don't have a physical install CD you will have the product key on a sticker on the hardware. I used an old XP product key from a broken laptop I have here and it worked fine.

When purchasing this you have to use the Windows 8 Upgrade Assistant. It assesses your current system to see if it can run Windows 8, so bast to run it on a PC you either intend to install it on, or you know will pass the test. Once tested it asks what you will wish to keep after the upgrade. Select "none" and you can then make the program download the Win 8 installer. Once that finishes you can select to make a DVD ISO to burn or copy the installation files to a USB flash drive.