bait-and-switch
noun [ C or U ]
ukus MARKETING
a method of selling in which a product is advertised at a very low price to attract customers, who are then persuaded to buy a different product at a higher price:
It seems to him that many brokers have been doing a bait-and-switch, luring customers with low rates and fees, then increasing those costs near the closing date.
bait-and-switch tactics