The Handkerchief Bills by Rakuten would definitely make me feel like a rich billionaire using money to wipe the beads of sweat off my forehead. Donning Japanese currency, these handkerchiefs will also make you feel like an international business mogul.
Currently the Handkerchief Bills by Rakuten are only available in Japan. If they ever decide to go world wide I bet they would easily become collector items with people trying to get one in every form of currency.
More Stats +/-
Dollar Bill Marketing
Currency Origami Art
Colloquialism-Covered Cash Holders