search engines: Second site Name your price

SATURDAY LUNCHTIME, 30 October, and the pumpkins are stacked to shoulder height outside the local grocer. That isn't surprising, since at pounds 6 they're double the going rate. By the time darkness falls, they're down to pounds 5. The price remains where it is until the middle of the following week, as do most of the pumpkins. There are few things more pathetic in the world of commerce than an overpriced pumpkin on 1 November.

It would never happen on the Net. Most traders would prefer to slash their prices for time-sensitive items than not to sell them at all. But price is not the only barrier. When something is about to pass the moment at which its value collapses, its vendor has to make contact with potential customers in a hurry. Naturally, e-commerce has stepped forward, offering the ability to connect individual customers with constantly updated stock inventories. Airline tickets are ideal material for last-minute trading: the airline ticketing system was one of the first markets to be computerised, and an empty seat is worth less than nothing at 30,000ft.

One British-based Web enterprise has turned the idea of last-minute trading into a brand and a lifestyle choice. Lastminute.com claims that its mission is "to encourage spontaneous, romantic and occasionally adventurous behaviour". It does so by showering a confetti of offers with an accent on leisure, such as flights, holidays, hotels and theatre tickets. Some of the participating traders indicate the size of the discount; others keep the information to themselves.

Lastminute.com also gives its visitors the chance to jump on the e-commerce bandwagon of the season, via its auction section. While much of the appeal of on-line auctions must lie in the prospect of picking up bargains, their success seems to suggest that consumers enjoy competing with each other, as well as enjoying the benefits of competition among traders. On-line auctions give them a new angle on shopping.

Auctions are more of an occasion than a regular way to shop, but they are not the only means of trading that allows customers to set prices. A third way has been developed by a US venture called priceline.com. Even though its supermarket deliveries are confined to the New York area, it's worth a look, because it might just be the start of something big. Much of what's on offer at priceline.com is time-sensitive stuff like airline tickets and hotel rooms, but customers can also shop for items across the whole breadth of the consumer scale, from groceries to cars, trucks and mortgages. Priceline.com invites them to name prices for the products they want. It relays the bids to the suppliers, and then informs the bidders whether their offers have been accepted.

The tone is much more sober than at lastminute.com, treating customers as the rational operators beloved of classical economics, instead of urging them to make purchases on impulse. Would-be bidders are advised to shop around for hotel prices in the area where they want to stay, and to make reasonable offers that are likely to be accepted. Cereals and nappies are mentioned as examples of the goods for which customers are invited to name their prices. Once the bids are accepted, customers pay on line, then print out the list of pre-paid goods to present at the checkout tills.

It may be a long time before British shoppers are offered a service like this. But it's nice to note that one British supermarket has succeeded in putting together an Internet service deal which, on paper at least, looks perfectly formed. Waitrose.com offers free access and free 24-hour phone support; its discs work on Macs as well as PCs, and it gives its takings from on-line phone charges to charity. All that and democracy too: users can vote on which charities should benefit, the money being distributed by proportional representation.