I'd like to add an API_KEY for GoogleMaps
for testing and in documentation I've read this :
Tip: During development and testing, you can register a project for testing purposes in the Google Cloud Platform Console and use a generic, unrestricted API key. When you are ready to move your app into production, register a separate project for production, create an Android-restricted API key, and add the key to your application.
My question is, do I have to put my Credit card even if it's a testing API_KEY? I do not get the purpose to put my Creadit card to use Google Maps, isn't it free?