It was a very big ratings tactic when AM radio was losing to FM in the 70's. The local station would give away free radios in supermarkets, high school football games, parades, etc.... WIP-610 in Philly gave away a few hundred thousand of them, the tuner permanantly set to 610AM. A very expensive way to grasp for market.
...the tuner permanantly set to 610AM. A very expensive way to grasp for market. Not necessarily. To pick up a strong AM station, all you literally need is a diode, crystal earphone, and ground.
So a box with diode, batt, speaker, volume-off switch, and "WIP-610" in "big friendly letters" was probably pretty cheap.
Come to think of it, even though its "our" money, the State Department was giving away shortwave radios in Cuba last year.