Not sure if this has been posted as far as clean installs go but...
In Windows 8, go to Control Panel and then Recovery. In there is an option to create a recovery drive. I have not played with this yet but the description says, "Create a recovery drive to refresh or reset your PC..."
Looks like this will create a recovery drive using USB media but I'm not sure to what extent of cleanliness the installation is. It looks like if you pick the Reset option it will then wipe out everything and do a fresh install.
Might be useful for creating 'install' media for this $15 upgrade.
From what I've read it'll do a completely clean install but you can actually use a command prompt command to manually overwrite the stock image (say, after you've installed drivers), pretty useful either way if you can't get the media any other way and/or don't run other image backup software.