It’s a common marketing technique that also happens to be illegal. Bait-and-switch means that customers are drawn in with an alluring offer, then flicked over to an item that’s more profitable.
This is often done by denigrating the special deal once the customer is in the store. “It’s a nice vacuum cleaner, but we can’t include a guarantee.” Or “Frankly, you’re too classy for that suit.”
A sophisticated version works like this. You want cosmetic work done on your nose. The first consultation, including a diagnostic examination and X-rays, is very reasonably priced. You’re happy to go ahead.
Then you get the quote for the operation, which frankly looks outrageous. But by then, you know the doctor (who is a nice person) and paid for the preliminary work. You’re in the system.
Bait-and-switch is hard to prove, which is why vendors get away with it. In all cases, you have no obligation to complete the purchase. It’s painful to start again somewhere else – but can hurt more not to.