I recommend the "Little House" series by Laura Ingalls Wilder, which is about her pioneer family's life and many moves further and further West as the Territories were being settled (in the US). The series follows a somewhat fictionalized version of Laura's life from age 6-ish to the early years of her marriage. The series is more aimed at older children than adults, but it's still very enjoyable. The first book is Little House in the Big Woods.
There are other families they know that are "rich," but I don't remember Laura ever considering her family poor.
I loved the Little House books, to the point that when the TV series started I was horrified that Michael Landon was playing Pa--"he doesn't even have a beard!" (give me a break, I was seven)I was surprised in my adulthood to learn that two events on the show that were not in the books--the birth and death of the baby brother and the Ingallses running a hotel--actually happened. Pioneer Girl, Laura Ingalls Wilder's first manuscript on which the Little House books were based, was published a couple of years ago--heavily annotated, I might add--and boy, were those books cleaned up. The Ingalls family was extremely poor.
I loved
Pioneer Girl, but it's not fiction in the same way the others are.
In the same vein,
The Worst Hard Time, about the Dust Bowl and Great Depression, was wonderfully sobering and
really put life into perspective.
Another one that's not fiction but reads like fiction, I can never recommend
Mrs. Mike enough. It's about a young woman who, in the early 1900s, was recommended to go north to Canada (from Boston) for her health. She met and married a Mountie when she was 15 and they ended up moving up to the Yukon. It's one of my favorite books. It's not about poverty per se, but they definitely didn't have much and endured quite a lot.