> Marx agrees that money and exchange play a role in a
> transitional society
No, he doesn't:
"Within the co-operative society based on common ownership of the means of production, the producers do not exchange their products; just as little does the labor employed on the products appear here as the value of these products, as a material quality possessed by them, since now, in contrast to capitalist society, individual labor no longer exists in an indirect fashion but directly as a component part of total labor." (Karl Marx, Critique of the Gotha Programme) <http://www.marxists.org/archive/marx/works/1875/gotha/ch01.htm>
-- Lew