Problem
The billing template for a customer's membership is set to $0, which is why it shows $0 during the billing run.
Solution
Follow these steps to correct the billing template so it reflects the correct amount for a customer's membership run.
Go to the customer page.
Go to the Membership where the billing template is inaccurate.
Edit the membership.
Change the billing template amount from $0 to the correct amount.
Save your changes.
Run the billing for the customer again to confirm the update. For more details, see Process recurring billing for memberships
Following these steps, you should see the correct amount for the customer's membership run.