You also need to say how much power you can provide? Do you have 30kw of available power running to your house? I have around 5th of hashing because...I don't have enough power in my house(at any price) for more devices.
This is a very good point. Just because you have 'free' electricity doesn't mean that in infrastructure of the place you are renting (it would be very unlikely that someone who owns some kind of location would have free electricity) has an unlimited capacity of wattage. It is also unlikely that a 'place' that offers free electricity would allow you to modify the electric setup to allow for greater capacity.
Why is it so hard to believe that some people have free electricity.
I also have free elictricity at my office i rented.
The electricity cost are charged at a fix flatrate.
However I tried with some miners and office became loud and miners run hot, so I cannot use my unlimited electric power.
This is another issue that the OP could face. The OP will need to have enough physical space to house the miners in a place that would insulate him from the noise and the heat (although the heat issue could be mitigated by the fact that the OP could use more electricity to cool the location)