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.
I was able to see this problem in your jotform http://www.jotform.ca/form/51755082536256
the issue is being caused by erroneous condition rules that updates the Price textbox.
I suggest you re-design the form and use Calculation Value instead.
user guide: -How-to-Assign-Calculation-Value
and remove the condition rules that update the Price
You can check my test form http://www.jotformpro.com/form/51761003398959
You can clone the test form also. -How-to-Clone-an-Existing-Form-from-a-URL so that you can check in your Form Builder how I setup the form.
Let us know if you need further assistance.