Whether you prefer a vintage look, hate the idea of perfectly good tables, desks and dressers going into a landfill, or just want to save money, second-hand furniture can be a great alternative to buying new. In general, pieces made of wood or metal will be your best bet. Patio furniture that’s free of mildew also is a great category to buy used. Mattresses and upholstered items like sofas could carry pet dander — or even bedbugs — so proceed with caution.