Even though cash was in short supply during the Depression, children were still encouraged to save their pennies in a "piggy bank", but sometimes they were not shaped like piggies at all. Insurance companies and banks gave out such money collection banks.
My mother found three of them from Aid Association for Lutherans, Appleton, Wisconsin when she was cleaning out a drawer lately. All three are shaped like books about 4 1/2 inches tall and 3 inches wide. As you can see from the picture, they are all about the same shape, but have different coloration in them. They are from the 1930s when she was little, but I can't imagine why AAL would have made a different tin book bank every year, or why Mom's parents would have had three different banks for only one little girl.
The book banks have keys (she still has two of them) that can unlock the bank to get out the hard earned money that was saved - most likely a penny at a time.
There is a slot on the bottom of the book banks where the dollars or coins would be inserted to save - maybe for Christmas. I bet Mom and Dad would keep the key so that the children couldn't open the bank and take out their hard earned money to spend early.
Maybe one of these tin book banks will end up in one of my novels sometime. That might be a good idea.
I'd sure love to hear from anyone who has any memories of these banks, or why a company would make so many different ones during the Depression.