Character Analysis
You can't fool us that easily, but even we were surprised when a Fool randomly showed up with Apemantus while the creditors are waiting outside Timon's house. What is he doing there?
Well, you should know, first of all, that this dude's name refers to his job description: a licensed fool was a guy who literally had a license to say whatever he wanted without getting into trouble. Paid fools were pretty common in noble households in Shakespeare's day...
Shakespeare Loved a Fool
... And boy, did Shakespeare love him some fools: he gave Feste in Twelfth Night and the Fool in King Lear some of the wittiest lines in those plays. There are even fools in Othello, As You Like It, The Winter's Tale, and The Tempest—to name just a few. So when we see a fool crop up in this play, we want to make sure to pay attention. Usually, Shakespeare makes his fools smarter than the other characters.
See what he did there?
The joke is that even the fool can outsmart the other characters, so it's actually the other characters who must be the foolish ones. This play is no different: while this Fool's on stage, he manages to figure out the creditors pretty quickly. He observes: "When men come to borrow of your masters, they approach sadly and go away merry. But they enter my mistress' house merrily, and go away sadly" (2.2.102-104).
Translation: standing out here waiting for Timon's money, you're like men waiting for prostitutes. Ouch. The Fool's able to see through things pretty clearly, and you know, it's totally true that these dudes are turning friendship into a financial exchange, just as prostitution turns sex into a financial exchange.
Too bad the Fool isn't there to tell it like it is from the very beginning.