Dear Sridhar,
Growing banana is a tight rope walk in a way although to start with it looks very simple and there are dozens of "fair weather friends" helping and advising till you till you start losing your crop then they vanish. Correct cultivation cost is about Rs 80/- for the first year per plant. Do a serious job look for a experienced but definitely qualified consultant as returns are high. Also go for minimum 6 to 10 acres cultivation. Do not waste time and money in learning and experimenting such learning is not sufficient for venturing. Sorry for being straight forward.