- Prime Day began at midday today offering exclusive deals to Prime members
- Retailer has extended this year's event to last until midnight tomorrow night
- But consumer experts warn shoppers to prepare and research their purchases
Shoppers are expected to spend more than £2.5billion on Amazon Prime Day today, but a consumer watchdog has said the bargains are not always what they seem.
Industry analysts expect sales to be up 42 per cent from a year ago amid the global shopping extravaganza which began at midday in Britain today and will last 36 hours.
But watchdog Which? have said that some items are cheaper at other times of the year.
Adam French, the Which? consumer rights editor, told the BBC: 'Although these time-limited sales events can offer great discounts, not all offers will be as good as they seem.
'It can be easy to get swept along by the hype and excitement on the day, so we recommend preparing in advance and researching what you want to buy, to make sure you can tell the difference between a good deal and a dud on Amazon Prime Day.'
One IT consultant, Jonny Grant, said the price of a computer monitor went up from £299
Jonny Grant, an IT consultant from London, found that the price of a computer monitor on Amazon Prime actually went up at midday on Tuesday, from £299 to £354.
He told the BBC. 'I didn't buy it, because I wouldn't want to reward them for this kind of price hike.'
Amazon Prime members have been given access to exclusive deals across product ranges including beauty, furniture, televisions, games consoles and films.
Prime Day was created by Amazon in 2015 to mark its 20th anniversary, and was launched last night by Take That who performed a gig to 400 people in London.
Amazon has extended this year's Prime Day to last until midnight tomorrow night, which is causing a headache for competitors in an increasingly tough marketplace.
A spokesperson for Amazon told the BBC: 'One of the great things about shopping online is that customers can quickly and easily compare prices.
'For many of our deals the new price and the previous Amazon price can be seen at the product detail page so customers can make an informed decision.'
Charlie O'Shea, lead retail analyst at Moody's, said it 'ratchets up the pressure on all of retail' to roll out big deals 'in hopes of attracting shoppers and dollars'.
Coresight Research said it expects Amazon's sales to be up 42 per cent this year compared to 2017 Prime Day, but other analysts warned shoppers to be careful.
Adam French, Which? consumer rights editor, said: 'Although these time-limited sales events can offer great discounts, not all offers will be as good as they seem.'
He added that consumers should prepare in advance and research their purchases to ensure they can 'tell the difference between a good deal and a dud'.
The Seattle-based retailer has put on twice as many deals on offer for this year's Prime Day compared to last, and will also have flash sales every few minutes.
Several companies have agreed to launch new products on Prime Day today – such as a Fingerlings unicorn doll whose horn lights up.
The company is also pushing its school supplies, after customers bought more pencils, pens and lunchboxes on 2017 Prime Day than any other day of the year.
The event was extended from 24 to 30 hours last year, which helped the retailer have more Prime sign-ups than on any other day in its history.
Last year's Prime Day also saw 32 per cent of all subscribers buy something – and the company's turnover soared 50 per cent on the previous year.
Amazon now has more than 100million paid Prime members – and Australia, the Netherlands and Singapore will all be a part of Prime Day for the first time this year.