Why is it that discussion of the sophists and sophistic activity routinely mentions the fees they charged, but never explores why the sophists might have charged fees and why this rather mundane detail would warrant such regular reiteration? I argue that the sophists charged fees to demystify the ways in which gift-exchange made it possible to naturalize culturally established values and misrecognize power relations as relations of generosity and friendship. By charging fees, the sophists showed that trade in skillful political discourse was always tied to the pursuit of advantage and power. This critical practice was rejected by Socrates, so that when his students needed a way to highlight the distinctions between their master and other teachers and schools (since in the popular mind all alike were sophists), they fixated upon the fees the sophists charged as a distinguishing trait. As a result, it took on the form of a stigma, and has been remained a defining charge against the sophists ever since.