The radio provided an instant source of advertising. In order to be profitable, radio stations had to sell advertising spots since their product was free. Many of the early radio shows had corporate sponsors. Fans of the show were often fans of the product advertised before the show. In many circumstances the advertisements were targeted for a particular audience; for example, a radio soap opera could carry Ivory soap or Martha White flour as a sponsor because housewives would be the presumed audience of the show.
Radio advertisements also made the advertising world more scientific. Many radio shows were popularized nationwide—not only did this create the largest possible market for products, but it also created large sample sizes for surveys concerning the effectiveness of advertising. Advertising agencies could now adjust their pitch in order to reach the largest possible audience.
Radio was also a constant presence in people's lives. For many people, the radio was a source of entertainment and news, as well as a lovely piece of furniture that no home should be without. Even people without radio could walk down the street and hear other people's radios. By the end of the decade radios were also in cars. The constant presence of advertising led to more impulse buys as well as advertisements targeting young people, who would then pressure their parents into buying things.
Radio, combined with more surplus wealth, boosted the American consumer economy. Pitchmen became famous nationwide by becoming associated with certain shows and products. Radio helped to fuel consumer demand for various goods and thus helped create the notion that the decade was good for everyone economically. Radio was important in making consumerism a major part of American culture.