# Reading a shelf price

The number on the shelf edge is a public claim about what something costs. It is a useful claim, and it is not the number on your receipt. Several things sit between the two, and all of them are knowable before you reach the till.

## The shelf price is the standard price

Most airport retailers of any size run a loyalty scheme, and members pay a different price. Where that is so, the shelf frequently carries both, and the member price is the real one for anyone who signs up, which is usually possible on the spot in a couple of minutes. A comparison between one shop's member price and another's standard price is not a comparison at all.

## Where you are flying can change it

A number of shops price by destination. Whether your flight leaves a customs area, and which country it lands in, can change both the tax treatment and the price list applied at the till. The assistant will ask for your boarding pass; this is one of the reasons. Expect the possibility rather than being surprised by it.

## The currency on the ticket

Airport shelves often show two or three currencies. They are conversions at a rate the shop chose, applied at a moment the shop chose, and they are not equivalent offers. If your card is in one of them, pay in the local currency of the shop and let your own bank do the exchange, rather than accepting the terminal's offer to charge you in your home currency at its own rate. The same applies to the shelf: read the local currency figure as the price and treat the others as a courtesy.

## Crossed out numbers

A crossed out price is a claim about a previous price, not about value. It may be the standard price of the same bottle last month, or the price of a different size, or the standard price the member discount is measured from. Where a shop shows both, the number you pay is the one that matters, and it is the one we record; the crossed out figure is kept separately as what it is, a claim about the past.

## Promotions, bundles and the second bottle

Two for offers are a saving on two bottles and a cost on one. Bundles that add a glass, a miniature or a pouch are worth the value of the extra to you and nothing more. These are not tricks; they are simply priced on the assumption that you will not do the arithmetic while boarding is being called.

## What the date is doing on our prices

Every price on this site carries the day it was observed, because a shelf price is an observation and not a standing fact. Prices move with promotions, ranges and exchange rates, and a figure with no date attached is a figure you cannot weigh. Use the recent ones with confidence, treat the old ones as a guide, and [compare the shops on your route](/savings) before you commit.