Need help with boyfriend of four years

[lisas]

My boyfriend and I have been together for 4 years now. He is not legal her and does construction framing for a living. As we want get married and start a family, I must find out how to sponor him or change his status.  If we marry,

1)  what is the average cost of sponsorship
2)  would he have to leave the country, and if so for how long and by what means?
3)  should we apply while he is here or away?
4)  is he better off applying as a spouse or a skilled worker?

All these question.. I am so confused!

Please help.