Does Jotform take a percentage of payments?

Does Jotform take an additional percentage of payments?  Or is the only fee the paypal fee?

No. JotForm does not take any percentage from your Payment forms. 

Whatever amount you have setup on your payment integration will be the same amount that will be processed in the transaction payments. 

Please take note that if you see any extra charges processed in your payment form, it could be because you have setup the payment form to have the option. Or in your payment account (i.e. paypal) you have setup the account to process additional charges.

Let us know if you need further assistance.