How much is a 1589 coin worth?

Answer 1

Not nearly enough information to identify it.

First look for the word COPY in small letters stamped into the coin's design. In that case you have a so-called replica coin that's worth a dollar or two. If you can't find the word COPY it may or may not be genuine. You would need to know what country issued it, what denomination it is, and what metal it's made from.

Your best bet might be to take it to a coin dealer for in-person examination. However, it's extremely unusual for 400+ year old coins to just turn up so be prepared for the possibility that it's a copy or an outright counterfeit.
Depending on the condition of the specific coin $10 to $3000.