Can set a limit to the number of total submissions to a question?

You can use a Gift registry widget:

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

http://form.jotformpro.com/form/43155172335955? 

Another option is the Ticket Purchase widget:

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

http://form.jotformpro.com/form/41532262484957 

Both these widgets allow you to define the limit of that item, and they stop being available for selection after that number is reached.

Is this what you need?

If not please provide us more details so we can be of more assistance.