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.
You can limit the number of submissions that you can received, here's a guide that you can follow: http://www.jotform.com/help/137-How-to-Limit-Submissions-in-a-Form.
Unfortunately, we do not have a feature that limits per session or time.
But you can use widgets that has a limit of the number of times it can be selected.
Here's a sample form to see how the Ticket Purchase widget works: https://form.jotform.com/53561365008958
I hope that helps.