You have to investigate available hardware and then compute their mining ability taking into consideration other costs such as electricity, administrative costs etc.

To be quite honest, traders have got into this game since end of last year and the whole thing is messed up now. Its basically a dog eat dog world since traders don't intend to HODL and simply want to ride the wave to make a few bucks.

Unless you are smarter than the traders in the game, you won't make money, since they will take your money!