Retailers are readying themselves for another record Black Friday despite days of sales ahead of the event and warnings to consumers to disregard the hype and spend sensibly.
The global sales bonanza - originally a 24-hour affair - now comes after two weeks of intense effort by retailers to lure customers with bargains, yet is still expected to set another record on Friday as the UK's biggest shopping day.
Retailers are promising a fresh set of deals from midnight online, and a number of big-name chains are extending their high street opening hours to cope with expected customer enthusiasm.
Among them are some John Lewis stores that are slightly extending their opening hours, a "few" Argos outlets opening early and 187 Tesco Extra stores that are closing at 1am and reopening at 5am on Black Friday, while a further 62 will open at 6am after preparing for the event.
Tesco said last year's Black Friday, which lasted a week for the supermarket giant, saw more than six million visits to the Tesco Direct website, a 40% increase on a typical week.
Argos recorded its biggest-ever day of sales last year and John Lewis had its biggest week for sales in its 153-year history.
However, experts point to the event moving increasingly online and expect high street figures will be up just 4% on last year, with past scenes of in-store brawls over cut-price televisions unlikely to be repeated.
Britons are expected to spend £2.6 billion tomorrow alone - an 8% increase overall on last year - and £7.8 billion over the four-day period from Black Friday to Cyber Monday, up 7% on last year, according to predictions by VoucherCodes and the Centre for Retail Research (CRR).
Their figures suggest that Cyber Monday could even overtake Black Friday by £7 million to become the biggest day for online and offline spending this year, with an estimated 21.5 million Britons expected to take part in the traditionally online event.
A survey by consumer group Which? has already indicated that more than half of deals last year were the same price or cheaper months either side of the event and has urged consumers to research prices thoroughly before buying tomorrow.
MoneySavingExpert said: "If you were planning to buy something worth £100 anyway and it's 30% off, it's a saving. If the same item isn't on your list, it's a £70 cost."
Jo Causon, chief executive of the Institute of Customer Service, said: "Retailers should not view Black Friday simply as an opportunity to shift discounted stock. They must uphold a responsibility to ensure customers receive a high quality experience too."
Last year, 63% of people made a purchase on Black Friday, according to the institute's research, with an average spend of £185.
Ms Causon added: "Canny retailers should take note: customers are for life, not just for Christmas.
"Those seduced by quick sales and chasing revenue will do themselves a long-term disservice by selling out short-term customers. This is not sustainable and Black Friday isn't the answer to easing shareholder concerns."