Google Maps changed their APIs in June 2018. There are not free anymore as you have discovered and you need to create project and enable APIs there. Have no worries. You have 200$ limit that you can spent free of charge every month.
I think that for Location finder you will need to have "Places API" enabled but to really unlock full functionality of SXA Maps component, follow below steps.
Head to your project api list:
but you will be redirected to a page with list of apis:
which looks like this:
Enabled all APIs, with "API" at the end of their name + Places API for Web, like this:
with this list of enabled APIs at the end:
After these changes finally SXA map component with Google Maps started to work:
Once again. Have no worries enabling all of those APIs. You have 200$ month budget to spent and you are paying only for services that you use. You are not paying by number of enabled APIs!
More details can be found here: