I am not too sure whether there were some options, but there is something I have heard about: giving classes or teaching.
Very often when you read about the lives of the musicians, you hear them teaching the rich and often being flustrated at having to do it; since the rich are not onlways talented. But they need to do it to close their budget.
Answer:
exactly what I'm doing lol
He refers to the jazz age using instruments.
