PayPal Fees via Conditional Fields and Calculator

In this message you reference a way to add PayPal fees to an amount via conditional fields add-on and the calculator add-on. Since that topic was marked resolved, I thought I’d start a new one.

I cannot find any information on the calculator add-on other than this page I don’t see any reference to a calculator.

So my questions are:

1. Do I really need to buy the “Plugin Bundle” to get the calculator when I do not need any of the other features (E.g., 30 websites) that comes with it?

2. How will it work specifically?

3. Is there a demo anywhere of how this would work so that I can see it and make sure it accomplishes what I need before I purchase it?

Thanks for your help.