In this paper I present a business cycle model with one market sector that produces a standard good, and another that produces a non--market, or home, good. The model shows that business cycles can be driven only by self fulfilling expectations, although other shocks (e.g. to technology) may play a significant role as well. With respect to other models of this kind (e.g. Farmer and Guo ) the model does not require an unconventional upward sloping aggregate labor demand. The presence of either productive externalities or market power is of course crucial, but their magnitude is sensibly smaller than in comparable models. The time series that are generated have properties that are comparable to the real U.S. postwar series.