What is an old buck coin worth?

Presumably by "old buck" you mean an old $1 coin. However saying a coin is "old" isn't enough to have any idea of its value. The date, possible mint mark, design, and condition are all very important.

Please either:

- check your coin again and post a new, separate question with that information

- look for existing questions with the Wording "What is the value of a <date> US silver dollar, where <date> is the date on your coin.