How much is a ten dollar gold coin worth?

Answer 1

Much more information is needed. Is it an old coin (i.e. before 1933), or modern?

If it's old, what date is it, how worn is it, and what mint mark is on the coin, if any? In this case, please post a new question with that information.

If it's a modern commemorative, the "$10" denomination is artificial because modern gold coins are sold for their metal content and not for spending. In that case you need to look at the amount of gold it contains, as stated on the coin's reverse side, then multiply by the current price of gold bullion. You can find that on a lot of websites like cnnMoney, or in the financial section of any reasonably-large newspaper.