Less haggling, more time saved
When Mona Giamanco decided she wanted to buy a new car, she was dreading running around and visiting car dealers. So she joined the growing numbers of car buyers making their purchase through a third party referral.
In her case, it was Costco.
(Read more: More city dwellers beginning to steer clear of cars)
Last November, she picked out a Volkswagen Passat on the Costco Auto Program website. The retail giant put her in touch with a local Volkswagen dealer who had the Passat at a preset price.
Within 48 hours Giamanco bought her Passat for less than the inventory price.
"In the past I would hop from dealership to dealership, taking several weekends, combing the lots trying to get a deal," she said, "But this was so much easier."
Costco Auto Program sales surging
This year, Costco Auto Program is expected to sell 375,000 new vehicles.
Most of the members buying new vehicles are looking for three things: A good deal, no haggling and not to waste time.
"We really save the members a lot of time by doing all that legwork on their behalf," said Jeff Skeen, general manager of Costco Auto Program. "They would rather spend their weekends doing something else than haggling with car dealers."
Skeen says Costco car buyers wind up paying about $1,000 less than those who visit dealers on their own trying to get the best deal possible.
(Read more: Money worries keep Gen Y from buying, leasing cars)
The 3,000 dealers paying Costco Auto Program for referrals are part of the program because they'll make money down the road servicing the cars they sell. In addition, members tend to have higher credit scores, so closing deals is not an issue.
Is Costco Auto Program the way all cars will be sold in the future? No.
But Kaas and his McKinsey team say this is an example of how the car buying experience is rapidly changing.
"The consumer still uses the auto dealer. Those who can change with their customers will succeed," Kaas said.
CORRECTION: This version corrected the spelling of Giamanco.
—By CNBC's Phil LeBeau. Follow him on Twitter @LeBeauCarNews.
Questions? Comments? BehindTheWheel@cnbc.com.