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.
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I think that you should probably check our enterprise license, you can find it here: http://www.interlogy.com/products/jotform/
The highest plan that we have is the Professional ($49.95/month) and for what you're mentioning it seems that the best option for you would be hosting JotForm in your own secure environment and there you can add as much users as you want.
If you have further questions, please let us know.
I would like to add that in case you decide to stick with the http://www.jotform.com/ version, and you need more that 100,000 monthly submissions / 1TB Space / 100 Sub-user Accounts, we will be able to offer a custom plan.