Consumers are haggling dealers down by an average of £939 off the price of their new or used car.
The latest results from Auto Trader's Owners' Guide shows how far the market is currently skewed towards buyers, with three in five motorists paying under the asking price for a new or used car in the past quarter (July-September).
The report also suggests men are better negotiators when it comes to price - saving £300 more on average than women.
The average saving made by male motorists was £1,029 compared to female drivers £706. Auto Trader believes part of the problem is sellers misjudging the state of the market before pricing their vehicle.
Nathan Coe, group director of Auto Trader, said: “With so many sellers getting less than they were expecting for their cars it raises the question of whether this is people not valuing their cars appropriately or whether it’s buyers taking advantage of a weak market.
“Everyone knows buyers look at the state of the market before they purchase, but consumers have a lack of understanding about accurate pricing when it comes to selling.
Auto Trader believes dealers should do research through online valuation sites to prevent disappointment.
The findings come at the end of a poor period for sellers with advertised prices at the end of Q3 2012 being £376 lower than at the same point in 2010.
Although the top concern for sellers is not getting the asking price for their vehicle, many jeopardise their chances by choosing the most convenient way to sell (51%) rather than the one that may get them the best price (20%), further reducing the amount they will get for their cars.
However, Auto Trader’s Retail Price Index, which tracks the average asking price of used cars, indicates the situation is starting to improve for sellers.
Although advertised prices reached their lowest ever mark in July this year – and are £159 lower than this time last year - they have started to improve.
The average cost of a car increased to £8,711 over the quarter as a whole with prices in September alone increasing by 3%, indicating the market may not be tipped in the buyers favour for too much longer.
Coe said: "While it is a good time to buy, the market is starting to turn so buyers should not be complacent. Those who are willing to do their homework will usually get the best deals. It’s advisable to research the price and specifications of cars online ahead of making a purchase so buyers are armed with the knowledge and confidence that enables them to make more informed decisions."