A market whew disaggregated suppliers exchange good or services with disaggregated
denza~zders. Note that market models can apply to unpriced
goods and services. The main idea behind the market model is really
equilibration through exchange. Hence, the market model can be applied
to many phenomena other than the production and allocation of textbook
goods like widgets or apples.
For instance, you might try to understand the flow of patients into a
state mental hospital system in terms of supply and demand: there is ashort-run "supply" of available beds in state hospitals and a per-diem
charge for each, while there is a complex "demand" for their use generated
by police departments, county psychiatric emergency units, judges,
members of the public, and so on.