You have the 1c Franklin from the years 1890-1893. The stamp is common. To ensure you are looking at the correct stamp check that the stamps top frame looks like the image at the bottom left of this page. If the frame looks like that on the bottom right (with triangles in the corners) then go back to the previous page and select a stamp with that design.

To value the stamp click on the numbers 219-229 on the menu to the left.