'flutter_map' is in no way associated or related with Google Maps
Google Maps' home page: https://developers.google.com/maps Google Maps' pricing page: https://mapsplatform.google.com/pricing/ Google Maps' documentation page: https://developers.google.com/maps/documentation/tile/2d-tiles-overview
Raster 2D tiles from Google Maps is a relatively new offering, which makes Google Maps directly compatible with flutter_map, whilst abiding by the Google Maps' ToS (which the previous method did not).
Tile providers that also provide their own SDK solution to display tiles will often charge a higher price to use 3rd party libraries like flutter_map to display their tiles. Just another reason to switch to an alternative provider.
To display map tiles from Google Maps, a little more effort is needed, as they require a complex session token system.
Therefore, we haven't yet constructed a full guide, so please read the Google Developers documentation for more info: