I have a player in my game who wants to learn Draconic from his two party members in their downtime. Something that he was wondering about was why he has to pay 1gp if the party members are freely teaching him how to speak the language. In the 5e PHB, it says:
Training lasts for 250 days and costs 1gp per day.
Now, the question is, is that cost for paying the instructor or is it for something else entirely?