We are currently working to improve the Cloud Credits page; we've learned a lot from customer feedback about what is confusing. Until that new page is live, here are a few main points:

• There are two different types of resources which are metered. W|A API calls and Cloud Credits.
• W|A API Calls are really just calls that return W|A pods as results. Using = or == both would make W|A API calls.
• Cloud Credits are used for computations via a deployment and for specialized resources/tasks.
• Cloud users are NOT charged for computations while in a Wolfram Cloud notebook. While you are logged into Wolfram Programming Cloud or Mathematica Online, you have an assigned kernel. If a deployment such as a CloudCDF, Instant AP, etc. is being accessed, that is utilizing different resources which are metered by Cloud Credits. 100ms of computation via a deployment = 1 Cloud Credit.
• Semantic functions and entity calls (accessing the Wolfram Knowledgebase) consume Cloud Credits. 5 credits for semantic functions and 2 credits for entity calls.

WPC Free's monthly allotment of Cloud Credits was just increased from 500 to 1000 Cloud Credits. Very soon, we will also provide a large learning bonus to help users explore the language.

Thank you for your feedback and the constructive conversation. We are continuing to make changes based on what we learn.