The credits system for the Content Creator tool is call "SZ Words".  Essentially you are billed based on the amount of words our AI has generated for you.

If you run out of SZ Words, you can click on the "Add SZ Words" button to purchase more.

Included in a Spamzilla monthly subscription, you will get 10,000 SZ Words, please note that these credits are refreshed each month.  

You also have the option to purchase more SZ Words, the extra SZ Words credits that you purchase will never expire.