LocationIQ offers affordable, scalable and reliable location services since 2013. They serve 50k+ developers who make 2 billion+ requests each day. Their geocoding service can also be used within Maps Marker Pro after signing up for an access token.
That´s it. Afterwards you can start using LocationIQ geocoding when creating a new map or marker:
With their free plan, locationIQ allows up to 10.000 requests/day and a maximum of 60 requests/minutes and 2 requests/second
Larger plans are are available for higher usage limits.
When using batch geocoding or when ambiguous results are returned, any results within the provided bounding box will be moved to the top of the results list.
Change the default language of the results. You can pass two letters country codes (ISO 639-1). By default the language will be retrieved from the WordPress global variable $locale (with a fallback to en if not supported)