Going to have to be slightly sarcastic here but a market for labour.
http://www.aqa.org.uk/subjects/business-studies/a-level/economics-2140/subject-contentHowever in the section, you need to understand the Marginal Revenue Productivity of Labour theory (Demand Curve for Labour)
-How wage rates are determined in Perfectly Competitive, Competitive and Monopsony labour market structures.
-The effect of a Trade union on each of these structures in terms of wages and Employment
-The effect of NMW in each of these structures
-Discrimination
then Labour Market Failure and on to the Dist of Income and Wealth