A good depiction of the gritty realities and the meaning of material striving for the very poor in turn of the century farm life is the novel Independent People, by Halldor Laxness, an Icelandic nobel laureate.

Keep in mind that Halldor's book is depicting a situation fairly specific to Iceland: people recently freed from debt bondage, in a desperately poor and isolated area caught between much larger forces. It's not an attempt to accurately depict what it meant to be working poor for American laborers, like say grapes of wrath.