A pair of cloaks I made from thrift store scraps.
I started with a long strip of purple flannel-like fabric, and cut it into two smaller rectangles, roughly the same size and length. You'll want to measure the fabric up against your child, to see how long it should be.
I took an elastic thread, folded one end of the fabric down twice, about an inch wide, and straight stitched from one side to the other. then I pulled the thread tight, so that it made a sort of roushed or ruffled collar, stitched it at the end a couple times, to cement it, tied a knot and cut the off the excess.
Cut a length of narrow ribbon, and thread it through a tapestry needle(if you have one), or safety pin. Slip it through one end of the collar of the cape, and push it all the way to the other side. Make sure the two ends are even. On one end, slide a large wooden bead(or plastic, or a button), poke the tip of your glue gun into the bottom opening of the bead, squirt a teensy bit of glue in, and slip the tip of the ribbon into the hole, in the glue. Repeat with other end.