Anne of Ingleside by Lucy Maud Montgomery

It was not easy to earn money in the Glen but Jem went at it determinedly. He made tops out of old reels for the boys in school for two cents apiece. He sold three treasured milk teeth for three cents. He sold his slice of apple crunch pie every Saturday afternoon to Bertie Shakespeare Drew. Every night he put what he had earned into the little brass pig Nan had given him for Christmas. Such a nice shiny brass pig with a slit in his back wherein to drop coins. When you had put in fifty coppers the pig would open neatly of his own accord if you twisted his tail and yield you back your wealth. Finally to make up the last eight cents he sold his string of birds' eggs to Mac Reese. It was the finest string in the Glen and it hurt a little to let it go. But the birthday was drawing nearer and the money must be come by. Jem dropped the eight cents into the pig as soon as Mac had paid him and gloated over it.

-"Twist his tail and see if he will really open up," said Mac, who didn't believe he would. But Jem refused; he was not going to open it until he was ready to go for the necklace.