It is well known that Socrates did not receive payment for his teaching. Criticism of teachers’ accepting a salary was common among ancient philosophers, practiced notably by the Sophists. This refusal to receive a salary is based on a specific conception of the nature of philosophical knowledge itself, and on the relationship between the teacher and his pupil. This article seeks to examine the material and intellectual benefits that make teaching philosophy a rewarding activity that merits being chosen for itself, basing its approach on the works of Plato, Xenophon and Aristotle, in which the criticisms of salaried teachers are the most forceful.