What is JotForm?
JotForm is a free online form builder which helps you create online forms without writing a single line of code. No sign-up required.
At JotForm, we want to make sure that you’re getting the online form builder help that you need. Our friendly customer support team is available 24/7.
We believe that if one user has a question, there could be more users who may have the same question. This is why many of our support forum threads are public and available to be searched and viewed. If you’d like help immediately, feel free to search for a similar question, or submit your question or concern.
On the payment page, can I limit the total number of registrations accepted for any given class I'm teaching?
You can set a maximum number of submissions in a form, please take a look at this guide: http://www.jotform.com/help/137-How-to-Limit-Submissions-in-a-Form
Your second question didn't come completely, but I assume that you want to set a limit date to accept submissions. If this is the case, you can also see how to do this on the guide above.
Let us know if you need further assistance.