I am moving into a place in Buenos Aires, Argentina where power will be free. Power is cheap here anyhow. How much mining power do I need approximately to generate 1 btc a month?

I heard another way of mining is to actually buy mining power on line. You don´t have to worry about any equipment breaking down.  Is there a tutorial on mining and how to perform all the necessary calculations? What about a excel spreadsheet?

What are your thoughts?