The current pricing is free for 8GB (10GB or 1B rows read /month) or $3k/month unlimited? So not really possible to start relying on it for anything serious yet (except really serious).
The middle tier isn't even fully described yet, but does say 20GB limit (and from $29/month) - I suppose that means that's a base from which you'll be able to pay for more storage as needed.
https://turso.tech/