I didn't make em, but from the looks of it, Purdue used a thin orange linen bed sheet (or maybe bulk fabric) cut into 2in x 24ish? strips. Had to be incredibly cheap, maybe time consuming to cut them out.
That's a great way to do it on the cheap. At the IndieCade
and Come Out and Play
festivals last year, we gave out strips of fabric and two socks to all players. We also had the bandanas available for purchase, but they were not required