Bait and Switch

In retail sales, a bait and switch is a form of fraud in which the fraudster lures in customers by advertising a product or service at an unprofitably low price, then reveals to potential customers that the advertised good is not available but that a substitute is. The goal of the bait-and-switch is to convince some buyers to purchase the substitute good as a means of avoiding disappointment over not getting the bait, or as a way to recover sunk costs expended to try to obtain the bait. It suggests that the seller will not show the original product or product advertised but instead will demonstrate a more expensive product.
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Noun
1. a deceptive way of selling that involves advertising a product at a very low price in order to attract customers who are then persuaded to switch to a more expensive product
(hypernym) selling, merchandising, marketing

an illegal tactic in which a seller advertises a product with the intention of persuading customers to purchase a more expensive product; the swines!

a deceptive marketing scheme resorted to by consumer good vendors when they advertise a genuine product and offer it in the store, but... - (read more on Bait and Switch)