When I followed the link to http://spotify.com/us/googlehome/register, I got a message that I was on the list and would get an email when the device was ready. About 2 minutes later, I received an email with a link to the Google store that included the promo pricing ($0.00) at checkout.
i submitted my request for the free Mini and then received an email from Spotify that said "Your Google Home Mini awaits" so I clicked on the Get It Now button in the email. This took me to the Google store where I selected a color. Then it went to a page that said my bill would be $49.
uh, that's the normal price, right? where's the free version?