For existing Fi users, it's $450 off, plus another $200 in store credit for the Pro models (not money off since it's parked in Google Store, but if you're buying accessories or other items over the next year it's like money). Selling my old phone brings the price of a 10 Pro down to around $400 (not counting the $200 store credit).

If you sign up for Fi when buying the phone, the deals are pretty enticing: $300 off right away, $500 more in Fi bill credits over 24 months. I think you also get the $200 store credit too.