It is estimated eight in 10 shops are now offering Christmas discounts as retailers hope for record crowds over the next three days.
Fears consumers are reining in their spending ahead of Christmas were fuelled after the latest retail figures showed a 0.1% rise in November.
And according to a study by accountants PwC, 76% of high street chains are currently offering sales or advertising money-off promotions in their windows. This compares to 69% of retailers last week.
They estimate the average amount of money being discounted on goods is 44%, meaning there are plenty of bargains on the high street.
The early sales arrive as the British Retail Consortium revealed muted activity so far this December, with the numbers visiting shopping centres over the month to date falling by 5% compared to last year.
The Scottish Retail Consortium reported total sales in November fell by 2.7% in real terms, compared to last year, prompting fears the tills would not be ringing this Christmas.
According to local government and trade sources, confidence on the high street remained low as the UK prepared for what is traditionally the busiest shopping weekend of the year.
One survey showed 84% of town centre managers stated the level of confidence among shoppers in their personal financial positions has either not improved or has got worse compared with this time last year. It was suggested the particularly cold and wet start to the winter could also be taking its toll on the number of shoppers visiting town centres.
But things could change as the last-minute Christmas rush begins this weekend.
The high street continues to face stiff competition from the internet. Data released by the Office for National Statistics earlier this week showed internet sales accounted for almost 11% of all purchases in November – the highest level recorded since the series began in 2006.
But high-street retailers are fighting back, offering money-off deals to attract customers away from their computers, phones and tablets.
The Gap sale is already on, while Marks & Spencer and Sainsbury's are expected to launch early in-store sales on Christmas Eve, and Debenhams is offering up to half price on Christmas gifts.
Stuart Patrick, chief executive of Glasgow Chamber of Commerce, said 2012 has not been an easy year for retailers but added feedback received from the St Enoch Centre and Buchanan Galleries indicates pre- Christmas performance is encouraging.
He added: "Despite this, there is never any room for complacency, with stores struggling against a tough economic backdrop and the impact online shopping has on consumer habits.
"Taking this into account, any predicted boost will be extremely welcome on the high street, but I'd like to hope Glasgow's retail core is sufficiently positioned to tackle the challenges presented in the New Year, with confidence reinforced by the quality of brands in the city centre."