An instance of Ubuntu from a pre-prepared image, in exchange for $0.00 and your contact details.

The pre-prepared image part does perpetually have value - it saves you installing from a standard ISO and Azure-ifying the result, or having your own image pre-prepared from earlier.

It is a short while since I last spun up a fresh VM in Azure so I'm can't remember if this arrangement is made clear at all, though I do remember getting an email like the one discussed at least once last year.