In what way does Billy earn money for his dogs?

One day, he finds an ad in a magzine for two coon hound pups at $25 each from a Kentucky kennel. He decides to save money by selling stuff to fishermen, and picking berries and skinning hides for his Grandpa's store. He puts the twenty-three cents he has into an old K. C. Baking Powder can. He works hard through the summer and the next one. After two years, he has fifty dollars. His Grandpa is shocked, and cries over Billy's hard work.