Real Dictionary

bait and switch
phrase: Bait and switch is used to refer to a sales technique in which goods are advertised at low prices in order to attract customers, although only a small number of the low-priced goods are available.

bait-and-switch in American English
of, related to, or employing an illegal or unethical sales technique in which a seller lures customers by advertising an often nonexistent item at a bargain price and then attempts to switch their attention to more expensive items
adjective: denoting a deceptive method of selling, by which customers, attracted to a store by sale items, are told either that the advertised bargain item is out of stock or is inferior to a higher-priced item that is available
noun: an act or instance of such practice