(price depends on whole list of factors such as: qualifications of teacher, place where teacher teaches, upright /grand piano, how long is your lesson, whether the teacher has lots of students, not caring to take one more, or is really desperate to teach more students, private lesson or at a piano retail shop? )
My fresh grads charge $ 250 an hour.... is that the type? I know a piano retailer place, charges $ 400 for a month for 45 minutes. (don't know the type of teacher...)
Can't answer this. You are asking more like a survey?
If charge under $300/hr is cheap, over $500/hr is expensive, but this fee is not for in-house teaching. Normally the experienced teachers will charge double if need to teach at students' home.
I want to ask you a question, if your boss jump up your rank and more work load for you but your salary remain unchange. Are you willing to stay in this job position or do you feel happy? Make a "Fair" exchange !!