@scruffy A lot of things happen in different ways and at different times in the novel, so it's not very clear cut.
That said this one scene (Maomao telling Jinshi about how to lower a courtesan prize) happens at volume 2 chapter 11
https://creativenovels.com/80/volume-2-chapter-11-value/
https://www.novelupdates.com/series/kusuriya-no-hitorigoto/
You are better off just reading from the start of vol 2 tho, just in case. You may miss some things otherwise.
The translation covers eight volumes so far, so you have material for a while. (And, unlike most LN translations, it's actually legible!)