Renting party dresses and designer separates for special occasions and big events is often more cost-effective and environmentally sound than purchasing (and storing) garments that will likely be worn just once or twice. With the rise of the sharing economy, Rent the Runway’s innovative rent-not-own model has been embraced by over 9-million members, and the company currently stores over 450,000 items in its 300,000 square-foot dry cleaning and warehouse space. Alas, the American start-up no longer ships internationally, and neither does Armarium , which specializes in loans of four-figure frocks for very special occasions.