Subject
3 free books about value, free to read online. Chapter 1 of any book is free, no account needed.
Social Value: A Study in Economic Theory, Critical and Constructive
Benjamin M. Anderson
An introduction to the theory of value: On the lines of Menger, Weiser, and Böhm-Bawerk
William Smart
The Measure of Value Stated and Illustrated With an Application of it to the Alterations in the Value of the English Currency since 1790
T. R. Malthus