From Mapping in the Cloud by Michael Peterson
All Google Maps API examples here use a key that is assigned to a specific server. You may need to acquire your own key. If the Google Map examples below don't work once you upload them to your server, you will need to get your own key from Google. As of July 2018, the Google key requires that you enter a credit card. The first $200 of usage is free. This equates to about 28,000 maps a month, more than most developers would need.