How about the old cotton bandanna.

Emergency bandage, tourniquet (when used with a stick), snot rag, hat, sweatband, water filter, pot holder, small ground cloth to keep food and small part out of the sand, mop, blindfold, a handy way of carrying nuts or small parts, cleaning cloth, restraint, gag, sunshade for neck when tucked under hat, cut up as gun, cleaning patch field-expedient loincloth (light line around waist), marking flag, distress marker, fashion accessory.

Not too shabby at $3 for two.

A step up is the slightly larger and thicker triangular bandage for about $2 each.