Now your mobile phone can help you be a smarter shopper.
A service has just been launched that checks to see if the goods you are thinking of buying in the real world are cheaper online.
In response to a text message containing the barcode of a book or CD, UK-based Scan will send back a list of how much e-tailers are asking for the same product.
If companies such as Amazon or Jungle are asking less for the same CD, Scan subscribers can buy it straight away by sending back another text message.
“We buy it on their behalf,” said Robert Hamilton, founder of Scan. He added that people seem to be happy to wait a couple of days to get a CD or book if they can get it slightly cheaper.
Although some shops use their own barcodes to track the goods they are selling, Mr Hamilton said that so far it had not proved to be a problem.
Every book has a unique ISBN number that the Scan service uses and barcodes on CDs are standardised across Europe and are always printed somewhere on the label.
The messages are sent using the Short Message Service (SMS) that is available on all the latest mobile phones.
In Europe, these short text messages are hugely popular. The GSM Association says mobile phone users send around 1 billion of them every month.
Although SMS messages are limited to 160 characters, Mr Hamilton said this was enough to give shoppers the information they needed.
So far the Scan service only covers books and CDs but soon it will be extended to almost anything that has a barcode.
But he said that people were not just using Scan when out shopping, some were using it when visiting friends who recommend a book or played a CD they had just bought.
Scan is proving popular with the cash-rich and time-poor people who like to get their shopping done when they have a spare moment.
Mr Hamilton said the idea for Scan came to him while in a bookshop and was born out of his own frustration as a shopper.
But like many other ideas for a net business others are working on the same technology too.
In fact, three US companies, IQ Order, Airclic and Barpoint, are trying to do more with the humble barcode.
IQ Order has built up a database of information about a huge range of popular products.
Subscribers to the IQ Order service can find more information on the goods and compare prices. The information can be delivered to mobile phones or handheld computers with a wireless connection.
Both AirClic and IQ Order want to use scanners connected to mobile phones or handhelds that will read the barcodes.
The companies want to embed extra information in barcodes to tell people more about the wine, CD or book they are buying as well as use it to compare prices.