How do I add a Processing Fee to Paypal

I can't seem to add a Processing fee to my form. On Formstack I was able to charge a small $5 processing fee to my form. I cant seem to figure out how to do this on JotForm. Please help.

Thanks for the reply. I think I have figured out the PayPal issue. I am now trying to figure out how to automatically send a confirmation response email. I have done everything that it says to do, but I am yet to receive an email. I've done it twice and responded to an email send and again, nothing. Help. :-)
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I checked your form and you currently have an autoresponder set up but you do not have a notification. 

Autoresponders are sent to the user filling out the form, based on an entry in an email field:

http://www.jotform.com/help/26-Creating-a-Form-Autoresponder

Whereas notifications are sent to a specific email address (yours) and are sent to the same address every time the form is submitted.  You need to set up one of these in order to receive an email when the form is submitted:

http://www.jotform.com/help/25-Setting-Up-Email-Notifications

If you have any further questions, let us know and we will be happy to help.