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.
In order for you to set a limit on the amount of products to sell, I would recommend you to use our Intventory Widge, do as follows:
1 - Open your form in edit mode, from the widget section, drag Inventory, the Inventory Settings screen will pop up, fill in the blanks, as shown below:
Notice that you are also able to include a picture to your product, click Finish button when done:
Please take a moment to read this guide: http://www.jotform.com/help/252-How-to-Add-a-Widget-to-your-Form
I hope this information helps.