This nice illustration by Jim accompanied an article by Ely Waters about cars with radios in them. Since radios back then had vacuum tubes, they could be very expensive. The first commercial car radio debuted in 1930 for $130 (almost $2000 in 2021), which could be 25% the price of a car.
I love this line from the story: “If you have a son who drives like a lunatic and every time the telephone rings after eleven p.m. you are afraid to answer it because it might be the hospital or the morgue, give him a car radio. It will cut his speed in two.”