Sold as a set of 5, as is.
Kissi was used to buy kola nuts, fabric, tobacco, wives and slaves. They are said to have a soul. When one of them breaks, the soul escapes and the iron piece does not have its value any more. Only the witchdoctor of the village (the blacksmith) has the power to reincarnate the soul by rejoining the pieces together.
It is even printed on Liberian currency today, as a memory.