The phrase "red cent" refers to a small unit of money, typically a penny or a small coin. It is often used to imply that someone has no money or is very broke. Full definition
But then I haven't spent years declaring that if a person has taken one red cent from the petroleum industry that person is morally flawed beyond redemption. (nofrakkingconsensus.com)
I might never make a single red cent writing fiction, so maybe I should just quit now. (lawyerist.com)