Depends where you are.
Here in Canada 1st year apprentices make 50% journeymen rate. 2nd year 60%, etc.
Not sure what its like else where. I doubt if you will get a job/apprenticeship while still being in school.
Don't do residential. Its the fucking worst. Avoid refrigeration as well since maintaining food storage equipment means on call 24/7 which sucks. Light commercial seems to be the sweet spot or if you don't want to drive around doing service, get in a big company and do new construction.