Fees

My mom said she used to pay Rs 20 for 12 Carnatic Classical music classes in 1969 when the world was relatively pure and business was worth the money.
Thats about Rs 1.75 per class. Classes were one to one (tutor to pupil and not mass).
She also said she used to pay 20 paise for bus charge from Malleswaram to Yeswantpur.

Extrapolating to 2009:
Bus charge from Malleswaram to Yeswantpur is Rs 5.
Thats an increase by 25 times.
So, a 25 times increase of Rs 1.75 is roughly Rs 45.

This gives a fair idea of how much the charge should be for a Carnatic Classical music class.
If 8 classes are held in a month, monthly fees should be anywhere between Rs 350 and Rs 500.