The Cunninghams are poor but they work hard for anything they have. Walter Cunningham Jr. is too proud to take money from Miss Caroline because he knows he can never pay her back. In Chapter 2, Scout tries to explain this to Miss Caroline who does not yet know the family history and social conduct of Maycomb:
The Cunninghams never took anything they can’t pay back—no church baskets and no scrip stamps. They never took anything off of anybody, they get along on what they have. They don’t have much, but they get along on it.
Scout also notes that when Atticus represented Walter Cunningham Sr., Walter was unable to pay him. Atticus was well aware of this and explained to Scout that Walter would find a way to pay somehow. Eventually, Walter did pay Atticus back in stovewood, hickory nuts, smilax and holly, and turnip greens. The Cunninghams are farmers and the crash (the Stock Market Crash of 1929) hit farmers hard. When Atticus represented Walter, it had to do with his entailment. The land that was not entailed (staying in Walter's name) was mortgaged and all the money Walter made, being a farmer, went to the interest accrued by the mortgage. Therefore, he never made cash profit and had to pay for any services in goods.
As was mentioned in the previous post, the Cunninghams are a poor farming family that has recently suffered because of the current economic crisis. Despite being poor, the Cunninghams are respected throughout the community of Maycomb. They do not have the money to pay people for their services, but they find other ways to repay people what they owe. Notably, the Cunninghams never take anything they cannot pay back. Scout mentions that Mr. Cunningham paid Atticus for his services by giving him stovewood, hickory nuts, smilax and holly, and turnip greens. Later on in the novel, Atticus tells Jem and Scout that the Cunninghams have not taken anything off anybody since they migrated to the New World. This level of independence is something that the Cunninghams are very proud of and continue to maintain despite their current situation.