The average commoner makes the equivalent of 1 gold per week.
90% of people are commoners, most are subsistence farmers. Farms host a variety of crops and livestock, to diversify food sources (in case of poor harvests). Some towns had communal sheep herds to reduce need for traveling shepherds. Days are spent working the farm and making clothes for the family: spinning thread, weaving, dyeing, sewing.
Commoners gifted surplus crops to other families as a form of social currency. This made it more likely others would support them in times of need.
In towns too small for a city guard, people in distress would give a special shout to indicate they were in trouble.
Nobles were able to focus more on maximizing profit and developed systems (serfdom, tenants/sharecroppers) to get the labor they needed. In most settlements, bht best farming-enhancing resources are owned by the nobles: plows, powered mills, draft animals, etc.
A slim minority of the population filled specialist roles, such as merchants, shepherds, fullers and dyers, and metalworkers.
Premodern cities were surrounded by miles and miles of productive countryside referred to as the hinterlands (largely farms and pastures). Transport by river was about 5x cheaper and by ocean 20x cheaper than by land.
Cities served as a hub for markets (selling things), administration, and militaries. Mortality in cities was very high due to constant disease outbreaks.
Cities and towns generally hosted "market days" once per week to ensure connection between commoners and merchants. This allowed merchants to travel around a circle of cities to get new goods and reach new customers.
Annual and semi-annual fairs were hosted to coordinate the exchange of hard-to-acquire goods and to focus on specific industries, such as clothes or metalworks. These were usually coordinated to coincide with prominent religious and cultural festivals.
More developed cities had alcoves for traveling merchants to set up or otherwise covered marketplaces to keep buyers and sellers comfortable. Some larger cities had multiple marketplaces, each for different goods. Permanent shops did not exist until a middle class developed that could afford to shop whenever it wanted.
Artisans tended to live in alleys near the marketplace. Smithies and tanneries were often not allowed in the city proper due to the smells.
Merchants were disliked in almost every premodern culture- by commoners because they violated community norms, and by nobles because they accrued wealth.