I had the same problem. You have to fill in your creditcard or bank info in order to get an API from Google. The prices are as followed:
-Mobile static map: free unlimited use
-Mobile dynamic map: free unlimited use
-Static map: free till 100.00 loading actions *
-Dynamic map: free til 28.500 loading actions *
*This includes the $200 Google gives to you as a gift every month.
I know it’s a bummer, but it is the only way to use Google Maps on your website.