I imagine rent is rather low in rural incestville and most people with minor cooking experience and a decent spice rack can make large, healthy meals at a low cost that most kids will eat (think rice, beans, corn, tomatoes, bit of paprika, bit of cumin, lots of pepper, little Olive oil, in a 1:1.7 ratio of rice to chicken stock, baked in a covered baking dish at 375F for 80 minutes, then topped with cheddar and some peanuts - you can easily make three pounds of that sorta stuff for 4 or 5 bucks).
A tugboat can probably get her quite far if she lacks the ambition to provide a better life for her kids, with college, up to date tech, allowances to be able to socialize with others of their age at public venues and so forth (after all, I suppose as long as they follow her particular creed, they are already living the best possible life in her mind, even if they are isolated from society).
It's a bit disconcerting if you think about it. People with higher educations and better careers that contribute more via taxes are less likely to have as many kids as those that do not fulfill these criteria and live what is essentially a parasitic (using the term purely from the pov of a system of government) lifestyle - the latter are, from an evolutionary standpoint, better adapted. After all, they pass on their genes more than the "elite" do. Case in point - M. L. Scott.
