You can try Gemini in BigQuery at no charge until January 27, 2025

Gemini for Google Cloud release notes
November 14, 2024
You can try Gemini in BigQuery at no charge until January 27, 2025. After that date, to continue to use Gemini in BigQuery you must do one of the following:

Purchase and assign BigQuery Enterprise Plus edition reservations to projects that use Gemini in BigQuery.
Purchase Gemini Code Assist Enterprise.
To learn more, see Purchase Gemini in BigQuery. These purchase options are now generally available (GA).