JotForm is a free online form builder which helps you create online forms without writing a single line of code. No sign-up required.
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.
For "Free" plans, you are allow to receive 10 completed payment submissions monthly. This means, if the user submits the form and was able to successfully complete a payment transaction, then it will be counted as 1 payment completed submission. You can check the difference of each account type/plan in our pricing page.
However, if you are just using the "Purchase Order" setup under the "Payment Tools", then it won't be counted as a payment submission because there's no 3rd party payment processor involved (ex. Paypal, Stripe, Authorize.net, etc...) that will actually capture a real payment. You can find the list of payment integrations here: http://www.jotform.com/help/323-Mastering-Payment-Form-Integrations-with-JotForm
Do let us know if you need more information on this.