[clarkevans]

It's not hard to work finance into all sorts of interactions. Take making cardboard sandals on a blanket outside. You can bring out all of the raw materials: cardboard, string, tape, paint, etc. List the prices for each. Then, figure out how many sandals were made. Add up the costs, and compute the average material cost for each pair of sandals they make. Girls get into it. One might even say: "yea, but we worked on this too; doesn't that count?" You can then factor in labour cost. Then, comes a few eyes that get big: "wow, $2.45 in materials and $5 in labour" (they debated and agreed it'd be great if someone paid them $5 for the hour they spent). Lots of lessons emerged: labor can be the dominant factor in product construction; and noone was really going to pay $7.45 for the cardboard sandals.