General Motors plans to help US dealers save as much as $150 million a year through a new Internet site that will offer discounts on office supplies, equipment and services, the Detroit News said. Designed and operated by Covisint and Reynolds & Reynolds, the GM Dealer Supply Advantage website, due to be launched on June 24, will be available to GM's 7,500 Buick, Cadillac, Chevrolet, GMC, Pontiac and Oldsmobile dealers, the newspaper said.