That depends on the size and age of the coin. A small, young coin wouldn't be worth more than $200, but an old, large coin would be worth about $200k.
Yes, but ..
It depends on its rarity as well. Some "large old" coins can be very common among collectors and sell for only a bit more than their metal content. You need to know several things -
> What is the coin's date?
> What is its denomination?
> What country issued it?
> How worn is it?
> If it's from a country that uses mint marks, what is its mint mark?
Without those facts it's simply not possible to give a blanket answer. If nothing else, though, they would be worth whatever gold is worth at the moment. It would take more information to determine whether they are worth more than that.