My paper seeks to explore Marx’s value theory following a Temporal Single System Interpretation (TSSI) of Marx’s determination of commodities’ values by labour-time. I explore how trying to consistently follow Marx’s definition of productive and unproductive labour affects our understanding of circulation/retailing. I model, trying to follow the TSSI of Marx, retailing sequentially occurring alongside production. Firstly I contrast how following Marx allows us to account for all the surplus-value extracted from labour, whereas seeing value as a market phenomenon cuts any link between exploitation of workers and profit. Then I explore how my model is affected in turn by a change to wholesale price, a change to retail price, and lastly a state of growth/technological change. Finally I conclude.