How can I limit product quantity?

I'm creating a conference registration form. Some of the events have limited seating. I did not see a way to limit the number of seats (products) that can be purchased. I thought I could have users enter an RSVP code into the coupon feature, since I can limit the number of times a coupon may be used. However, people may attend more that one event, and it appears they can only apply one coupon code. Is there a way for me to do this?

Unfortunately it is not possible to limit the number of seats (products) that can be purchased, with payment tool wizard.

Possible workaround is to use Ticket Purchases widget , Form calculation widget and donation option of payment field. You can perform calculation inside of your form and pass calculation to payment field. Inside of this guide you can find out how to perform calculation in the form:

http://www.jotform.com/help/259-How-to-perform-calculation-in-the-form 

You can also check this widgets:

http://widgets.jotform.com/widget/inventory 

http://widgets.jotform.com/widget/quantity_gift_registry 

http://widgets.jotform.com/widget/gift_registry 

Hope this will help. Let us know if you need further assistance.