Readings for Discussion:
Paul Bohannan, “The Impact of Money on an African Subsistence Economy,”  Journal of Economic History 19 (1959), 491-503 [on-line via JSTOR].

Robert D. Hof, “My Virtual Life,” Business Week (1 May 2006), available on-line.

Further Reading:
Keith Hart, “Heads or Tails?: Two Sides of the Coin,” Man new series 21:4 (1986), 637-656 [on-line via JSTOR].
J. S. Hogendorn and H.A. Gemery, "Continuity in West African Monetary History? An Outline of Monetary Development," African Economic History (1988), 127-146 [on-line via JSTOR].
E. P. Thompson, "The Sale of Wives" in his Customs in Common , pp. 404-466.
Michael Taussig, "The Genesis of Capitalism among a South American Peasantry: Devil's Labor and the Baptism of Money," Comparative Studies in Society and History 19:2 (1977), 130-155 [on-line via JSTOR].
James L. A. Webb, Jr., "Toward the Comparative Study of Money: A Reconsideration of West African Currencies and Neoclassical Monetary Concepts," The International Journal of African Historical Studies ( 1982), 455-466 [on-line via JSTOR].

Three papers on "virtual economies":
Edward Castronova (IU, Department of Telecommunications), "Virtual Worlds: A First-hand Account of Market and Society on the Cyberian Frontier" (2001), download from SSRN.
F. Gregory Lastowka and Dan Hunter, "The Laws of the Virtual World," California Law Review (2004), download from SSRN. --if you get very interested in these issues, you might want to compare the argument made by Jack Balkin, either in his book The State of Play (2006) or in "Virtual Liberty: Freedom to Design and Freedom to Play in Virtual Worlds," Virginia Law Review (2005), download from SSRN.