The full version is also free. It comes included with the Office365 installer, but can be downloaded on its own:
https://www.onenote.com/download
OneNote syncs to OneDrive - so if you have O365 your storage space is quite large, whereas free users only have 5GB (though compared to Evernote's 25MB this is still plenty)
Unless they've changed it quite recently, the version that comes with Office365 and the one from https://www.onenote.com/download are different programs.
OneNote syncs to OneDrive - so if you have O365 your storage space is quite large, whereas free users only have 5GB (though compared to Evernote's 25MB this is still plenty)