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.
Actually, customers can buy multiple ticket from your form, but you don't see it instantly. So, I've cloned and added this option to your form. You can check it from the below:
To add an total amount into your paypal payment tool,
1) Open the Paypal wizard.
2) Check the "Show total on the form" checkbox.
As it is seen on the demo, when you increase the quantity, the total value is going up.
If you encounter any error, please let us know.
Have a nice day.