Mary Beard, the “wickedly subversive commentator on both the modern and the ancient world” and blogger/author of “10 things you thought you knew about the Romans . . . but didn’t” gave this as Roman history myth #6:

THE PLEBEIANS WERE THE ROMAN POOR
OK Romans, just like us, did sometimes use the word ‘plebeian’ or ‘plebs’ for the ‘great unwashed’ (literally ‘sordida plebs’). But in the strict sense both ‘plebeian’ and ‘patrician’ were old hereditary divisions of the Roman people. These may once have signalled the poor/powerless versus the rich/powerful. But by the time of the later Republic there were enormously rich plebeians – like Marcus Licinius Crassus, the plutocrat who famously said that you couldn’t be counted as rich if you couldn’t raise your own private army.

I blogged about Crassus back in June:

Meanwhile, Crassus was helping out by setting fires to houses in Rome which he and Sulla wanted to claim. He also had a band of firemen and a real-estate agent on his payroll. As soon as the house began to burn, the agent would appear and offer to buy the property for a bargain price; the homeowner would agree, so that the house wouldn’t be a dead loss; and then the firemen would appear from out of sight and douse the fire.[26]

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[26] Hooper, Finley. Roman Realities, p. 223.

(The History of the Ancient World, p. 678.)