Even if you can't afford a 30-second network spot on "The Cosby Show," you can still get your message across on prime-time TV, provided you go through the right channels. By purchasing time directly from local stations, "we get twice the impressions per dollar as we would if we bought straight network," says Robert Bosworth, chief financial officer of Chattem Inc., a maker of health and beauty aids and specialty chemicals, based in Chattanooga. The company gets additional bang for its advertising buck by accepting "indefinite" time at a lower rate. That means the station guarantees a spot will air sometime between, say, 7:00 and 9:00 p.m., but not necessarily halfway through "Family Ties."

And just to make sure that it gets the best rates, Chattem uses a media-buying firm that, every six months, sends salespeople to the top 90 TV markets, where they meet directly with representatives of local stations.