All but the most eagle-eyed of online shoppers could pay more than they bargained for if they fail to take delivery charges into account, Halifax warned today.

This week is Home Technology Week, and many people looking for the latest gadgets now use price comparison websites, which trawl the web looking for the best prices.

According to industry figures, total sales in the travel and leisure, clothing, footwear and accessories, electrical goods and groceries sectors are now worth more than £1 billion a month.

But before placing your order you should look beyond the figures, because there may be a surprise waiting for unwary shoppers who think they have found an unbeatable deal.

A quick search for a 32" widescreen television reveals one online retailer quoting a price of £525 with free delivery, while a rival is offering the same model for £520. While this may seem like a saving of £5, there is actually a delivery charge of £34.99, which brings the total to £554.99 almost £30 more.

Similarly, one website advertises a cooker priced at £481.57, delivered to your door for free, while another quotes the same model at £477. Many people may think a saving of almost £5 is enough to secure a deal, but the latter price does not include delivery charges of £34.95.

It is also worth remembering that if a deal looks too good to be true, it probably isn't true. Sometimes goods are priced incorrectly on websites, but there is no guarantee you will be able to take advantage of this until your credit or debit card is billed no contract will exist and the retailer will usually spot the error before this happens.

In addition, some websites will not display VAT or delivery charges upfront, so you may only find out the true cost when you arrive at the checkout.

Peter Jackson, head of banking at Halifax, said: "Everyone likes a bargain, and the convenience of shopping from home means buying over the internet should continue to grow in popularity, but you should ensure you have taken all the charges into account before you place your order.”

"It's also important to use a reputable website so that your card details remain secure, and never send your details in an email, because these can easily be intercepted."