"GM dealers can go to the site to buy everything from office supplies to hardware from a variety of suppliers at one location," said GM spokesman Tom Henderson.
The GM Dealer Supply Advantage Web site will be supported by automotive industry exchange Covisint and The Reynolds and Reynolds Company, an information services company for the US automotive industry.
GM's Dealer Supply Advantage will allow dealers to become more competitive by offering them lower prices on products and services based on aggregated GM purchasing volumes, Henderson said. The more dealers buy, the more money they will save, he said. They can then pass on those savings to their customers, according to GM.
Henderson said dealers will pay $360 (£243) a year to access the Web site, but could reduce their annual procurement costs by 15%. Henderson said GM anticipates that about one-third of its 7,500 US dealers would sign on to the programme.
"But they would be the largest dealers who do 65% of the [sales] volume," said Henderson, who added that GM dealers spend nearly $1bn (£680m) annually on various materials and supplies.
Dealers will access the procurement Web site through GM DealerWorld, an Internet portal used by all GM dealers.