How much is $500 dollars?

I'm curious, could you please clarify for me the value of $500 dollars? Is it a fixed amount, or does it vary depending on certain factors? I'm asking because I'm interested in understanding the concept of monetary value in relation to the dollar currency. Additionally, would the value of $500 dollars be the same globally, or does it differ based on the country's currency exchange rates? Thank you for your time and consideration.