Help me understand Leaderboard pricing
The pricing plans are available here:

You will see Leaderboard Write Operations under each plan. This is how many times you can add entries across your leaderboards in a month. One use event occurs each time you save a name/score pair to a leaderboard. For example, in a scenario where 5 learners take your course one time each, and all 5 submit their scores to the leaderboard at the end of the course: you will use 5 credits.

You can display the leaderboard as many times as you want, displaying a leaderboard does not require any credits.

You can track your current usage and your remaining credits on this page:

There is a default email notification that goes out when you exhaust 80% of the credits for the month, so this will give you enough time to make arrangements if needed. You can choose to upgrade to the next plan if you’d like to keep using leaderboards in your courses or do nothing. If you run out of credits, you will not be able to use leaderboards for the remainder of the billing period, and the credits will reset with the next billing cycle. You can verify that the notification is turned on (or turn it off if needed) on the Account page.