I love the symbols. I am I have depicted two pigs facing each other.
The coins given to the piggy bank represent the food fed to a pig by a farmer. The only way for the farmer to get the money he invested into the pig back, is to slaughter it (break the piggy bank) and sell/eat the meat.
The pig is also a symbol of luck and good fortune, wealth, honesty, general prosperity, symbolizing a hardworking, peace-loving person, generous, indulgent, patient, reliable, trusting, sincere, sociable person, and humor. Pigs are also said to be a sign of virility. Prominently displayed in the bedrooms of couples trying for children.