I remember the most popular being Litecoin but what about now?

My electricity here is about 0.08/kWH and I heard a lot of news about the s5 becoming unprofitable. Will the s7 be profitable?

I currently want to join the vast network of bitcoin miners as a hobby. I do not expect to earn much but maybe in the $100 range per month.

What would be the best equipment to use? Would used equipment be better then new?