It used to be that you could have a map, or directions, load on your website and utilize Google Maps via its API, without charge. That changed in June 2018, and now just to get the map to load you need a unique API, and an active Google Maps developer's account with a credit card attached to it (gift cards will not work, must be a real card).
However, for most users, the $200. in free monthly credit supplied by Google for its Map API use will suffice. The API supplied will work across six websites (just open another account under a different email if you need more than six), and so long as there are under 25K page loads of the page that contains the map per month, you will not be charged. Since the Google Map is usually placed on something like the Contact Us page, even if your website is getting more than 25K views per day, still you probably won't have more than 25K visitors on your Contact Us page.
How to track your usage of the Google Maps API
However, for most users, the $200. in free monthly credit supplied by Google for its Map API use will suffice. The API supplied will work across six websites (just open another account under a different email if you need more than six), and so long as there are under 25K page loads of the page that contains the map per month, you will not be charged. Since the Google Map is usually placed on something like the Contact Us page, even if your website is getting more than 25K views per day, still you probably won't have more than 25K visitors on your Contact Us page.
How to track your usage of the Google Maps API