Credits are the internal currency used to apply for jobs.
Once you’ve used up all your monthly pre-paid credits, extra credits are charged at the specified rate and paid at the end of the billing cycle.
To check the usage and remaining credits, click Manage in the top right corner and go to Account settings > Plan & Payment
At the top bar, you will see the amount of:
Credits included in the plan.
Credits you have used in a current billing cycle.
Extra credits and their total $ cost.