My son is celebrating 100's day at school today. Here is the shirt we came up with:
We used an old tie-dye shirt (we make new ones every Summer), and I already had the scrap of fabric, fabric paint and googly eyes. I used some spray mount adhesive on the fabric and painted around it to keep in in place. Tacky-glue for the eyes, which my son placed. It won't be washable, but he only needs the shirt for one day.
Total cost: $0