Should I create a customer, subscription or charge?

Core Principals

Customer - A customer object stores the customer's details(first name, email..etc) and history of all charges/subscriptions. 

Example:

You want to store your customer's details to email them a promo code later for your business.

How do I add a new customer?

Subscription - If you add a new subscription, a customer will be created. A subscription is a repeated charge. It has a schedule for when charges are to be made. 

Example:

You are Netflix and have a subscription business model. This allows you the flexibility to set whatever kind of recurring charge to your customer whenever you want.  

How do I add a new subscription?

Charge - A charge can be created individually for one offs. Note: Creating a charge will not save customer details(first name, email..etc) under the Customer object.

Example:

If you are a charity and had a one off donor not wanting to be anonymous.  

 How do I add a new charge?