Geocoder is not generating my latitude and longitude

I have a section editor called "Events". In this section I have fields for:

address
city
state
zip_code
latitude
longitude

In my geocoder.php file I edited the following to include the "zip_code" field.

$GLOBALS['GEOCODER_ADDRESS_FIELD_COMBOS'] = array( // values should be ", " separated. alternates should be "/" separated.
  'address, city, province/state, postcode/zipcode/zip_code/zip',
  'city, province/state, postcode/zipcode/zip_code/zip',
  'province/state, postcode/zipcode/zip_code/zip',
  'address, city, province/state, country',
  'address, city, province/state',
  'postcode/zipcode/zip_code/zip/address',
);

However, when I create and save my event records, Geocoder does not auto-generate my latitude and longitude.

I tried changing the field zip_code to zipcode and zip, but neither of these worked either.

Is Geocoder's ability to auto-generate latitude and longitude for records dependent upon having a Google API with a credit card on file?

I'm stumped and can seem to get this working.

Zicky