I got an email from Google 2 days ago regarding the same problem. It says that Google still provide free tier for user. The free usage is equivalent to $200 per month. Adding credit card to your billing info will be able to add a coupon to your account that increases the limit to $500 per month.
I attached the screenshots here so you can see the details:
One big note in this announcement is that all fields that don’t have API key won’t work any longer.
So, I think in short terms, the Google Maps field still works if you already have a API key. However, in long term, we should figure out a better way. I’ll check Open Street Maps to see if we can integrate it.