multiple databases in the same project

[Dutyfree]

Good afternoon, can I create several databases with a free account? Or does it require billing to be enabled? In this case, how much and where would I have to do the payment process?

[Frank van Puffelen]

Multiple databases can only be added to projects that are on the Blaze plan.

Neither of the databases that are part of Firebase charges money per database, they purely charge for usage

All information regarding the cost is shown in the pricing page.