Print out using a picture manipulation program or a desktop publishing program and adjust the size to fit you or your childs face. Cut out and glue fabric to one side and trim – then repeat for the opposite side. Tie a ribbon that goes well with your fabric to both sides that can be tied around head. Trim with ribbons around edges, or dangling, sequins, or any other findings you want. Think feathers, boas, plastic spiders (for Halloween), tiny ornaments (for Christmas), bows, paper cutouts, and beads.
Also consider these a childs activity at a party… then can be painted or drawn on in marker or crayon. Print out a size appropriate for children and trace onto poster board and cut out. If they are going to paint, color or draw directly onto the paper it will need to be stiff because they wont have the extra strength from the fabric on both sides.
This could also make a great invitation: make with one side covered in fabric that goes with your parties theme and print the information for your party on the back. It would fit in a legal sized envelope so no special purchase would be required.