How to Add Variable Amount for Donation Form

I need a Paypal Donation Form for a Political Candidate which allows variable donation amount with a cap of $100.
My initial plan was to just use the basic Paypal and the Donate button. The government regulation made the process more complex.

Requirements

1. Accept donations in varying amounts up to $100
2. Federal & State Requires collecting Employer/Occupation for political contributions

This is my first outing with any Gravity Form Add-on, so excuse if I've missed something obvious.
I successfully installed/activated/configured the add-on and created the Paypal and Donation form.

I saw some references to a 'Donation' button. However also saw that this has been deprecated.
The new solution did not seem forthcoming and I could not find any solution on how to enter donation amounts.

Question
How do accept a variable donation amount?

I would like to be able to mimic the Paypal donation button of allowing the donater to choose the amount of donation.

The pricing fields:product does not allow for variable amounts. Nor does it allow a range of values to choose (that I could see)

I tried the Pricing Fields:Option with radio buttons. However the form requires a Pricing Fields:Product entry to save the form.

From my perspective I need to be able to have the product field as an input field which can accept input from the user or the ability to put a choice of numbers (i.e. $5,$10,$25....)

Any ideas on how to move this forward are greatly appreciated

My first preference would be for the donating party to leave whatever amount they choose up to and including $100. If that option is not possible, I was going to give a range of donation options ($25, $50,....)

Doh!!!
I found the different field types for pricing field:Product right after posting my first response ( and before seeing your second response)
I guess I didn't do enough RTFM due diligence. I agree with your assessment on the way to proceed. Thanks for your very quick response.