White fabric, Styrofoam ball (size depends on how large of a ghost you want), white string, heavy duty tread and needle, black marker.
These are easy-to-make ghosts to adorn your trees or fences. Take a large square of white fabric and lay a Styrofoam ball in its center. Then, wrap the fabric around the ball and fasten it with white rope or string, creating the flowing body of the ghost. Next, use a needle and thread to add a heavy duty thread or string to the top of the ball/head. I like to loop it through several times if I'm hanging the ghost outside in the elements. Make a large enough loop out of this to hang on a branch. You can also easily draw a simple face into the covered ball, if you wish, with a black marker.