Although I admit this title is unlikely to draw a high level of interest among your average elementary population, and it’s not exactly a part of the usual core curriculum, so it may not find a huge audience, I still give it a recommendation.  It offers a clear and concise description of how banking and investments work to return interest on money saved, including explaining the differences between different types of savings accounts and different kinds of banking institutions. The examples it offers uses simple numbers, easy for children to understand.  I think it wise that every library collection should have something along this vein to encourage students to understand the value behind saving money.