Ma, along with Pa, run Ma and Pa General Store. Ma, like Pa, is elderly and makes a brief appearance from the backroom of the store. When Pa rings up Hank's items at the cash register, the total ends up being more than Hank has on his person. Pa then generously tells Hank that he's not worried about a buck here or a buck there, and that people should come before pennies. After Hank exits the store, Ma appears where she's seen having a heated argument with Pa over his overgenerous gesture.
In the episode Snow Job, Ma is shown appearing from a backroom at Ma and Pa General Store where she's seen having a heated argument with Pa.