What happens if the free credit is not sufficient?

If the free credit limit of US$200 per month is not enough, you have the option to pay for further use on the basis of usage, billed either via a credit card, or, via Ubilabs, against an invoice. The Google Cloud Console lets you keep full control of your costs. Here you can set up quotas to suit your budget. 

We can provide you with a non-binding calculation and help you estimate the monthly costs - maps@ubilabs.com.