In other words, you pay market value for it, it doesn't include advertising, and Google is contractually obligated not to snoop on your content.
Which is why even Google competitors use this hardware, because the legal and technological protections are strong enough they don't worry about Google stealing their IP.
It would presumably work exactly the same way as Google's existing videoconferencing hardware:
https://workspace.google.com/products/meet-hardware/
In other words, you pay market value for it, it doesn't include advertising, and Google is contractually obligated not to snoop on your content.
Which is why even Google competitors use this hardware, because the legal and technological protections are strong enough they don't worry about Google stealing their IP.