Question: how much are used door knobs worth?
Answer: Prices for vintage glass knobs vary widely, depending on condition, rarity, style, and color. For the most common, 12-sided molded-glass knobs, expect to pay between $30 and $50 a pair. Sets of six- or eight-sided knobs cost between $60 and $100, while a pair of cut-crystal balls can go for as much as $500.