What doe it mean by receive payments?

In the pricing, what does it mean by "receive X payments"? 

I have a basketball camp where I may receive as many as 200 enrollments in one month, each submitting a payment with their enrollment. This will occur 3 times each year. What is the pricing package that I would need to consider?

When you form collects online payment using any of our payment tools e.g. Paypal payment tool, the submission is counted as payment submission. Every plan has its payment submissions limit. For the free plan, the payments limit is 3 per month. More info: https://www.jotform.com/help/408-Understanding-Your-Account-Usage-and-Limits

In your case since you only need it at some point, you can upgrade to the Gold plan anytime you need higher payment submissions limit then downgrade back to your preferred plan when you don't need it.