contract law

2. Friday evening after closing, Sackett's Appliances placed an ad in its window: "This weekend only, five Whirlwind dishwashers, reduced from $1199 to $599! Shop early!" Martens saw the ad later that evening. She appeared the next morning at 9 a.m. when Sackett's opened its doors and stated to the clerk she would take one of the Whirlwind dishwashers. The clerk replied that the ad was a mistake; the price should have been $999. Martens demanded to speak with the manager and insisted on Sackett's honouring its offer to sell at $599. The manager said. "I'm sorry, madam, but that machine cost us more than $800. We cannot sell it at $599." Martens said Sackett's was in breach of contract and she would see her lawyer about it. Is Martens right? Explain