How did the radio companies such as nbc , whose actual broadcasts were free, make money

Radio stations principally make money through publicity.

Explanation:

Radio stations' profits are made through different activities, but the biggest part of it comes from advertisement time, there are other ways for radio stations to make money, since they don't charge for the service they provide to the citizens, like Radio Special Events, Syndication of Popular Programs, and Selling Newscasts to other Radio Stations .

some sort of sound device i believe.

there are many cases in the crucible where propaganda is present, the types of propagandas that are shown are: bandwagon, testimonial, transfer, and card-stacking. the crucible is mainly focus on the ancient beliefs that people from towns had, if someone didn’t follow the rules they would be punished.