I made both of our costumes from fabric I got at Joann’s (total was about $15).
Fred’s costume was the easiest… used one of my husband’s shirts as a guide, and just cut the fabric longer. Mine was much more difficult to make form-fitting. I didn’t feel like going through the effort to mess around with a zipper or anything — wanted it as quick and easy as possible. Because of this, I had to leave one side half open so I could actually get into it, and then have someone sew it shut on the night of the party!
My necklace is pom-poms threaded onto dental floss. Oh, and of course we were barefoot all night!