My son Jacob wanted a Jolly Green Giant Costume. I bought a green costume for under $10 and then covered it with leaves. The leaves were on a vine and I cut them off to sew them all laying flat like the Giant. For his head we cut a baseball cap that was too small for him and used just the top portion and covered that with leaves.
Just to make sure people knew what he was, we had him carry a basket of Green Giant vegetables, but it turned out that EVERYONE knew what he was!!