Google's Home Mini smart speaker was unveiled in 2017, and this is the speaker you'll get as part of the free promotion with Spotify — not the newly announced update to the Google Home Mini, which is named the Nest Mini.
It's a subtle difference, but one that might matter to you if you were in the market for the newer smart speaker from Google. That said, the Nest Mini costs $50 and the Google Home Mini through this promotion costs zero dollars.