Possible poor evaluation by car owners is turning vehicle buying into a hagglers' heaven.
Successful bartering has helped knock an average of £939 off the price of a car for buyers, a survey by Auto Trader found.
Men appear to haggle better than women, with male buyers managing to get an average of £1,029 knocked off the price of a new or used car, with women managing only £706.
Overall, around 60% of motorists paid under the asking price for a new or used car in the period July to September 2012.
The poll of more than 3,000 motorists also showed that 51% of sellers chose the most convenient way to sell rather than the method that may get them the best price.
Auto Trader group director Nathan Coe 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. Sellers should do research through online valuation sites to prevent disappointment."
However, Auto Trader warned that the market was beginning to pick up for sellers, adding that buyers should not become complacent.