my daddy has paid the rent and the insurance man is gone and the lights is back on (1-3)
Before those lights came back on, things were likely looking pretty bleak for the speaker. But once the rent is paid, and everyone who needs to get paid is gone, the mood suddenly feels lighter, literally and figuratively. The focus is on good times now and appreciating the simpler pleasures that the speaker can't really take for granted.
and my uncle brud has hit for one dollar straight and they is good times (4-6)
A dollar can go a long way when we don't have much to begin with. Even the simple act of playing seems like a real treasure here. Not having much money just might make us appreciate good times more than we would if we had a million dollars to bet.
my mama has made bread and grampaw has come and everybody is drunk (9-11)
Liquor is also a treasure here, too, since booze costs money. Little luxuries like these tend to feel even better when we're not sure when our next good time will come. It even seems like poverty has a way of bringing the family together to share what few luxuries they do have.