How much is a bit in today's money?

I'm curious, could you please elaborate on the concept of a "bit" in terms of cryptocurrency and its value in today's money? Specifically, I'm wondering if there's a standard or accepted conversion rate that one can use to determine the monetary worth of a single bit, and if so, what is that rate? Additionally, how does the value of a bit fluctuate over time, and what factors contribute to these fluctuations?