"Price fields" are the most basic field in Paperform for adding a price to a form.
The price field can be used in two modes:
1. "Question is read only" is turned ON
The price is fixed, and can't be changed by the submitter of the form. The price is set in the question configuration (as pictured above).
2. "Question is read only" is turned OFF
The price defaults to whatever it is set as in the "Price" configuration, but the submitter is free to modify this to whatever they would like. One big use-case for this field is donations, or pay-what-you-want products. (hint: this goes really well with the "Minimum price" configuration option, for setting a minimum amount that can be entered by the end user).
What happens when a price field is hidden with visibility logic?
When a price question is hidden with visibility rules, either on the question itself of on the page / section that the question is in, then its price is removed from the total of the form. This means you can actually use price fields to dynamically change the price with logic that shows or hides the price.