Fair Use under the U.S. Copyright Act is nebulous and a playground for expensive litigation. The most recent case in point is the Eleventh Circuit's second remand of Cambridge University Press against the Georgia university system. You will recall that professors at the Georgia university system copied portions of published academic texts and distributed the digital excerpts to students. The publishers sued for copyright infringement. The university system claimed fair use.
The trial court reviewed the four-pronged statutory test for fair use. As to factor three--the amount and substantiality of the portion used in relation to the copyrighted work as a whole--the trial court determined among other things that the professors needed to copy excerpts into the course materials since the cost of the published books was so expensive. Indeed, the marginal cost of distributing digital copies was nil compared to the cost of purchasing a hard copy book.
The Eleventh Circuit's opinion of October 19, 2018 instructs that the cost of the unpaid copyrighted use is not a component of fair use analysis.
This provision of the Act does not direct courts to consider the price of the unpaid use. If it did, then the district court's reasoning could tilt the third factor in favor of fair use even in cases of extensive verbatim copying.
Just because a user of copyrighted work can save money through non-permitted digital copying and distribution does not justify a finding of fair use.