Dio Chrysostom, The Fifty-Fourth Discourse: On Socrates 1
“Hippias of Elis, Gorgias of Leontini, along with the sophists Polos and Prodikos were prominent in Greece at a certain time and earned a fantastic reputation, not merely in the rest of the cities, but in Sparta and Athens too. They made a lot of money, both at public expense in some states and from certain aristocrats, kings, and private citizens, to the extent that each was able.
Yet, they gave many public presentations that didn’t have the smallest shred of thought to them, but were the kinds of words from which one can harvest money from fools. There was another man from Abdera, who was so far from gaining wealth from others was not only destroying his own inheritance bit by bit, but he eventually lost all his wealth pursuing philosophy. It is clear that he was foolishly searching for something that brought him no advantage.
Ἱππίας ὁ Ἠλεῖος καὶ Γοργίας ὁ Λεοντῖνος καὶ Πῶλος καὶ Πρόδικος οἱ σοφισταὶ χρόνον τινὰ ἤνθησαν ἐν τῇ Ἑλλάδι καὶ θαυμαστῆς ἐτύγχανον φήμης, οὐ μόνον ἐν ταῖς ἄλλαις πόλεσιν, ἀλλὰ καὶ ἐν τῇ Σπάρτῃ καὶ παρ᾿ Ἀθηναίοις, καὶ χρήματα πολλὰ συνέλεξαν, δημοσίᾳ τε παρὰ τῶν πόλεων1 καὶ παρὰ δυναστῶν τινων καὶ βασιλέων καὶ ἰδιωτῶν, ὡς ἕκαστος ἔχοι δυνάμεως. ἔλεγον δὲ πολλοὺς μὲν λόγους, νοῦν δὲ οὐκ ἔχοντας οὐδὲ βραχύν· ἀφ᾿ ὧν ἔστιν, οἶμαι, χρήματα πορίζειν καὶ ἀνθρώπους ἠλιθίους ἀρέσκειν.
ἄλλος δέ τις ἀνὴρ Ἀβδηρίτης οὐχ ὅπως ἀργύριον παρ᾿ ἑτέρων ἐλάμβανεν, ἀλλὰ καὶ διέφθειρε τὴν οὐσίαν τὴν αὑτοῦ συχνὴν οὖσαν καὶ ἀπώλεσε φιλοσοφῶν, ἀναισθήτως δῆλον ὅτι, καὶ ζητῶν ὧν οὐδὲν ὄφελος αὐτῷ.
Plato, Hippias Major. 282d–e
“If you knew how much money I made, you’d freak out. This one time, I went to Sicily when Protagoras was visiting–he was well-known then and older than me–and while I was less experienced, I made more than 150 minas in a little time. In one small town alone–Inukon–I made over 20!
When I went home with that much I shocked and awed my father and the rest of our neighbors. I think I made more cash than any other two sophists put together.”
[ΙΠ.] εἰ γὰρ εἰδείης ὅσον ἀργύριον εἴργασμαι ἐγώ, θαυμάσαις ἄν· καὶ τὰ μὲν ἄλλα ἐῶ, ἀφικόμενος δέ ποτε εἰς Σικελίαν Πρωταγόρου αὐτόθι ἐπιδημοῦντος καὶ εὐδοκιμοῦντος καὶ πρεσβυτέρου ὄντος πολὺ νεώτερος ὢν ἐν ὀλίγῳ χρόνῳ πάνυ πλέον ἢ πεντήκοντα καὶ ἑκατὸν μνᾶς εἰργασάμην, καὶ ἐξ ἑνός γε χωρίου πάνυ σμικροῦ Ἰνυκοῦ πλέον ἢ εἴκοσι μνᾶς· καὶ τοῦτο ἐλθὼν οἴκαδε φέρων τῷ πατρὶ ἔδωκα, ὥστε ἐκεῖνον καὶ τοὺς ἄλλους πολίτας θαυμάζειν τε καὶ ἐκπεπλῆχθαι. καὶ σχεδόν τι οἶμαι ἐμὲ πλείω χρήματα εἰργάσθαι ἢ ἄλλους σύνδυο οὕστινας βούλει τῶν σοφιστῶν.
According to this estimate, a mina in modern terms would be around $500.00 USD. So, Hippias may have made c. $75,000.00 on his Sicilian tour.