Looks like you have got some homework to do before buying a Bitcoin mining rig! Asking these questions is like trying to bake a cake without knowing the ingredients. Trust me, you do not want to bite into that! 

My advice is to do your research and make sure you fully understand what you are getting into. Mining Bitcoin has its ups and downs, and it is important to know all the ins and outs, including how it works, what kind of hardware you need, and what kind of returns you can expect. And don't just rely on advice from unverified sources, such as random individuals on online forums – take your time and gather all the facts before diving in.