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 later that evening . She appeared the next morning at 9:00 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 as 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 then $ 800 . We cannot sell it $ 599 . " Martens said Sackett's was in breach of contract and she would see her lawyer about it . In order for Martens to win she must show that :

a ) the ad was an invitation to do business

b ) that Sacketts gave her consideration

c ) that the ad was an offer

d ) there was a rejection of her offer