Genius idea for an elf Halloween costume! All you need from your local Goodwill is a stripped T-shirt, matching pants, a belt, and shoes! You might even already have some of these at your house! All you need to do is make the hat!
A rope bracelet - reminds me of making friendship bracelets back in the day. My right second toe used to go numb because I'd hook the end of the bracelet over it, and then knot embroidery floss for HOURS.