(read how to identify your stamp below)
You have the 11¢ Hayes from the years 1922-30. It is a somewhat common stamp and is worth no more than a few dollars whether used or unused.
To determine the difference the two varieties of the 11¢ Hayes one needs to look at the perforations. You will need a copy of the very common 1932 3¢ Washington (#720). A picture of which is shown below. Follow the instructions below