The commercial management part of this game is very undeveloped. Due to its inefficiencies, it goes unused by many managers, but it's mostly unused because it's very easy to make profit off of sponsors alone.
However, if you feel like messing around you can purchase the Commerce facility and assign any number of marketers to sell merchandise.
Once purchased, it is up to the manager to decide how many marketers to employ and what to assign them to. After each race, you can see how much merchandise you sold in the Finances page.
In Merchandise sales, you can see the combined sales of merchandise you sold and if you click on the blue text, it will show you specifically how much of each type of merchandise you sold as well. That's about all I can say for the Commerce facility.
