Google Fi new and existing customers can get the new Samsung Galaxy Z Flip3 for $400 off, a significant discount on its $999 price tag. There are a few caveats, of course, and you have to purchase the phone first and keep it on a Fi plan for 30 days before you get the discount in the form of a bill credit. But if you’re an existing Fi subscriber and had your eye on the Flip 3 anyway, this deal makes a lot of sense.

If you’re an existing Google Fi customer on one of its full-service plans — data-only plans are not eligible— buy the phone at fi.google.com and activate it on your plan. You have to keep the phone active for 30 days to receive the discount, which comes in the form of a bill credit.

Non-Fi subscribers have to activate the phone on a new full-service plan, and must transfer their existing phone number to Fi— if you choose to get a new number on your new Fi plan you won’t get the bill credit.

Your purchase of a new Flip 3 will also be eligible for a $150 credit to use on Samsung’s website, just order the phone before August 26th and register it with Samsung. With the stacked discounts, you’ll save $550 on the phone, a good deal for a brand-new device.

The Fi promotion is valid “while the promotion is live and available on the fi.google.com site,” according to Google, and the Samsung credit is valid through November 9th.