Found this on the Google One App, unsure if this will show for new users but I'm on a Google One 3 months trial (free). Using Pixel 4.
Valid for one $7.00 Google Play credit. Valid for movies, apps, games and more.
Limit 1 redemption per Google One plan. Open to participants whoreceive a promotional code from Google One. Not reloadable; no cash value. Offer ends 31 Oct 2020 and must be added to a Google Payments account by 31 Oct 2020. Once added, credit must be used on Google Play by 31 Jan 2021. Certain subscriptions excluded. Valid in Australia only. Must be an Australian resident, have Internet access on a compatible device and have or activate a Google Payments account, subject to Google Payments Terms. Age restrictions apply. See Promotional Balance Terms and Google Play Terms for more information. Promoter: Google LLC, 1600 Amphitheatre Parkway, Mountain View, CA 94043, USA