Definition: Given a real-life anecdote of a complex ethical situation, generate a suitable title that describes the main event/root cause of the situation. Imagine that the given text is a social media post, and you have to write the title of the post, so the users can decide to read the main text or not.
Input: Roughly a week ago, my gf's sister (highschool) approached me(univeristy) to help tutor her with a language she is learing (which I am fluent in), and specifically asked me how much I charge. Not knowing how serious the tutoring would be(might be just playing around, or possible a 2-3 hour session), I gave her my usual quote and she left me on read.

Just a few minutes ago while chatting with my gf, she brought up the topic of wanting me to help tutor her sister. I told her whatever I told her sister and now apparently she is a bit disappointed at me for charging her sister.

AITA ?

( sorry for possible bad English)
TL;DR 

gf's sister asked me how much for one tutoring session, I gave her my quote.
Gf kinda disappointed in me knowing that I tried to charge her sister for tutoring.

charging tutoring fee from gf's sister