before starting everything, what is your electricity cost? if this parameter isn't good enough(below 0.1 usually) than it's better to leave the whole mining thing alone, and go with the simply buying
besides this, here we recommend the s5 as a default miner to initiate with, but the s6 is coming this month, better to wait at this point
I would agree what is your electricity cost? Also with summer are you prepared to get heat out of your mining area?
Heat is a issue with summer mining if you have a lot of gear.