New York--Internet advertising company 24/7 Media plunked down $150 million Monday for a pair of Internet start-ups with key technology for handling high-bandwidth marketing. It bought IMake Software & Services, Bethesda, Md., and Sabela Media, Los Angeles, in separate stock-swap transactions valued at $75 million each. IMake specializes in software and services for joining standard Internet advertising and broadband advertising. Sabela, which has a large number of clients in Australia, provides advertising and tracking software to 24/7. After the mergers, 24/7 will have 145 software engineers. The company is locked in battle with DoubleClick, New York, for domination of the U.S. Internet advertising services market.