How can we make playing with money more understandable and meaningful for young children?

The observations on pages 48-51 interested me very much when reading it. When I looked at the pictures after I had read each observation, I wondered how old these children must be. I thought maybe they were five, six or seven, which in fact when I looked back on the first page of "The Right Price" I noticed that the children were five years old. It kind of shocked me how much interest they had on counting money and playing the shop game. One of the classes I used to work in a couple of years ago, the teacher had a wall full of circle time things (calendar, weather, pictures, coins, numbers, jobs, colors, sign language, etc.). But what interest me was that of the coins she had taped to the wall. I never really asked her about it, but I remember she went over the names of the coins and what they meant with the children. The assistant teacher in this class would create different themes in the dramatic play center (airport, salon, post office, hospital, shoe shop, etc.). She would build these things using creativity with boxes and recycled and donated materials. When she was done creating the center it was absolutely amazing. I would fine myself playing with the kids in it and taking on different roles. If I had fun, then I wonder how much fun the children had...probably 100% more fun. She would put the money inside of the center when she opened up the shoe shop. I don't really remember how the children reacted with the money, but I think they understood the concept of it but not the actual meaning of the coins. The classroom I work in now has a container full of one, five, ten, and twenty dollar bills and pennies, nickles, dimes, and quarters. I observe them playing with the money but not really counting it. Is this normal for their age? Is this how children of four years old learn the concept of money? By just playing with it and not really understanding the value or real meaning behind money? I really like this quote from the text (pg 48), "Playing the shop game allows the children to give shape to these conventional meanings, putting them in relation to one another. The children exchange money and goods, but also competencies, where each player generously offers to the others his or her personal wealth of coins, ideas, and abilities." That is where my question comes into play, "How can we make playing with money more understanding and memorable for young children?"