There's a good book on such jobs called "Nickel and Dimed"[1] by Barbara Ehrenreich, who went "undercover" and worked a bunch of such low-paid jobs.

A quote from the book:

"When someone works for less pay than she can live on ... she has made a great sacrifice for you ... The "working poor" ... are in fact the major philanthropists of our society. They neglect their own children so that the children of others will be cared for; they live in substandard housing so that other homes will be shiny and perfect; they endure privation so that inflation will be low and stock prices high. To be a member of the working poor is to be an anonymous donor, a nameless benefactor, to everyone."

[1] - https://en.wikipedia.org/wiki/Nickel_and_Dimed