20$ hps econolight ballast buzzin'

From what i've read, this is normal in old ballasts is it not?

In addition to that, I'm wondering what I can use to extract heat - the cheapest method? In the future I want to get a carbonscrubber

Soil? - Cheapest?

Is fertilizer necessary?

Ballast are a little noisy especially the older ones. I use a stand-up A/C (doubles as a dehumidifier.) in the room as well as a constant supply of fresh air via Vortex fan (expensive).
Growing indoors is not cheap!!
You are trying to create a habitat for a life.
You don't have to spend alot on soil. I don't know how big your room or pots are but good bags of soil are about $20+
Fertilizer is definitely important because this is the plants food.
I would recommend Fox Farm Organic fertilizers.