Understanding Gemini API Billing: Does the Paid Tier Affect Free Usage?

As I explore options to enhance my experience with the Gemini API, I’m contemplating switching to a paid billing tier. With the impending discontinuation of access to pro models for free tier users, this seems like a necessary move.

However, I have some crucial questions regarding how this billing structure operates. Specifically, when I enable the paid tier, does it still offer any free usage allowances? For instance, if I remain within the rate limits set for the free tier, can I still utilize those services without incurring charges, or does enabling billing mean that all my usage will start to be billed?

If anyone has insights or experiences with the Gemini API billing structure, your feedback would be greatly appreciated. Understanding this will help me make an informed decision as I consider upgrading to the paid tier. Thank you!