How to spot it
- The advertised price exists on exactly one configuration, and that configuration is out of stock every time you look.
- The cheapest option is greyed out rather than removed, so the price stays on the page while the product does not.
- A salesperson or a chat window moves quickly past the item you named to one they would rather discuss.
- The advertised item is real but the wait is measured in months, and the substitute ships tomorrow.
- The comparison table has the cheap option missing a column that turns out to be the one you need.
Why it works on you
You arrived having already made the decision. The work of choosing is done, the number is settled, and the only thing left is to complete it. Being told the thing is unavailable does not send you back to the beginning: it leaves you standing in a shop with a decision you have already made and one option in front of you. Forty dollars more is easier than starting again, which is the entire arithmetic the practice depends on.
What to do
- Treat an unavailable advertised price as the end of the visit rather than the start of a negotiation. The comparison you did is void, because the thing you compared is not for sale.
- Ask when the advertised item will be in stock and get the answer in writing. A seller who cannot answer is telling you something.
- Price the substitute from the beginning, against the market, not against the bait. It is a different purchase and deserves a different comparison.
- Screenshot the advertisement. In several countries an advertised price that cannot be supplied is itself the violation, and the evidence disappears when the page updates.
Where the law stands
In the European Union, Annex I of the Unfair Commercial Practices Directive lists bait advertising as unfair in all circumstances and needs no proof of harm: point 5 covers advertising at a price the trader has reason to believe cannot be supplied in reasonable quantity, and point 6 covers advertising an item and then refusing to show it, refusing orders, or showing a defective sample in order to promote something else. In the United States the FTC's Guides Against Bait Advertising, at 16 CFR Part 238, say the same in older language: an advertisement is not a bona fide offer if the purpose is to sell something other than what is advertised.
This is a description of published regulation, not legal advice, and rules in this area have changed more than once. The sources below are the primary ones.