ServiceCost

gs:ServiceCost Class

What a service costs. A free service says so explicitly rather than omitting the field, because absence reads as unknown.

Identifier (IRI)
https://schema.govfresh.com/v1/ServiceCost
Label
Service cost
Subclass of
schema:StructuredValue
Profile
services

The full definition is in the vocabulary file (Turtle). A static host cannot choose a format by request, so this page and that file are the two ways to read it.