A displayed price is usually an invitation rather than an offer

Two ways of describing the same shop window

To a shopper, a price label is a promise: this item costs that amount, and paying it completes the transaction. To most legal systems the label is something weaker. It is an invitation to the customer to make an offer, which the retailer is then free to accept or decline at the till. The distinction sounds like pedantry until a decimal point goes missing.

The consequence is that the customer, not the shop, is usually the one making the offer, and the contract forms when the shop accepts it. Until that moment there is nothing to enforce. This analysis is not universal, and some systems treat a displayed price as binding on the seller in at least some circumstances, but the invitation model is the more common starting point.

Why the offer sits on the customer’s side

There is a practical reason for arranging it this way. If a display were an offer, a retailer would be contractually bound to every person who accepted it, including after stock ran out, and would have no ability to refuse a sale for any reason. Putting the offer with the customer preserves the seller’s ability to decline, which matters for age-restricted goods, suspected fraud, quantity limits and simple error.

It also fits how shopping actually proceeds. A customer who picks up an item and puts it back has not breached anything, which is only coherent if nothing was concluded when the item was picked up. The analysis is at its most convincing in a self-service shop, and rather less so where a service is ordered and immediately performed.

Online ordering repeats the pattern deliberately

Web terms are usually drafted to reproduce this structure and to make it explicit. The listing invites offers; placing the order is the offer; the automated message that follows is an acknowledgement rather than an acceptance; and acceptance occurs later, commonly when the goods are dispatched. That sequence is chosen precisely so that a pricing error discovered between order and dispatch can be corrected.

Whether the drafting works depends on the local rules, on whether the terms were properly brought to the buyer’s attention, and on what the messages actually said. A confirmation that reads unambiguously as an acceptance may be one, whatever a clause elsewhere claims. Some jurisdictions also regulate the ordering process itself, requiring the trader to acknowledge an order and to let the buyer correct input errors before submitting it.

A mistake the buyer could see is treated differently

Where a price is obviously wrong — a fraction of the normal figure, or the result of a plainly misplaced decimal — most systems have some mechanism for relieving a seller of the consequences. Common law doctrines about unilateral mistake, and civil law provisions on error, both tend to ask whether the other party knew or ought to have known that a mistake was being made.

That produces an uncomfortable position for the bargain hunter. A price which is merely a very good deal is likely to stand; a price which nobody could honestly have believed is unlikely to. The line between the two is a question of fact, and it moves with the type of goods and the way the price was presented. Buying in quantity because a figure looked wrong tends to weaken the buyer’s position rather than strengthen it.

Advertising and pricing rules run alongside

Contract law is not the only track. Many jurisdictions separately regulate how prices are displayed and communicated, covering the indication of a total, the treatment of unavoidable charges, comparisons with previous prices, and the practice of advertising something that is not really available. Breaching those rules is generally a regulatory matter rather than something that hands the individual customer a contract.

The two tracks can pull apart, which confuses people. A retailer may be in the wrong with a regulator for how it advertised, while still not being obliged to sell at the advertised figure. Conversely, a business that repeatedly declines to honour prices it has published may find that pattern being examined even where each individual refusal was contractually permissible.

What actually happens, and where to check

In practice most retailers honour small errors, because the reputational cost of refusing exceeds the loss, and most also decline large ones. Where a business refuses, a complaint to the relevant consumer protection body is generally more productive than a contract argument, since regulators are interested in the pattern rather than in the single transaction.

Whether a display is an offer, what effect an order confirmation has, and how mistake is treated are all matters of local law with genuinely different answers between systems. Nothing here is advice about a particular purchase. If money has already been taken and the seller is refusing to supply, that is a different situation from a refused sale at a till — and it is worth putting to a qualified lawyer or a local advice service promptly, because any claim will run on a clock that a continuing exchange of emails does not pause.