I was a part of this coaching industry as a student, it is almost inevitable if you are applying for IIT. For a two year period, I shelled out approximately Rs400,000. That is around 9000 USD at the then exchange rate of around 45 INR to a US Dollar. This amount includes coaching, hostel charge, food, books, everything.

EDIT: And this is on the higher end of the spectrum. I had the privilege of going to one of the best IIT coaching institute.