Your lifestyle is going to depend on who you talk to. During my first year, the "newness" hadn't worn off yet, so, it was pretty cool to think of going to work. That'll fade away at some point, and you're just stuck with the fact that you have to go to work. The call out's will depend on the company. We had what was called guaranteed pay (think of it as salary) which says you'll get 70 hours of pay, per month, whether you fly or not. If you're on reserve, and not busy, you might not break that 70 hour mark, someone else mentioned perdiem (pay for the time that you're actually at work, and away from base) which can make your first year FO pay check look "livable" (bust just barely) if you're never working, you won't get the per diem, so, you won't make any cash.
We didn't get paid any hours for being on call, at home, and not working. So, it's nice to run around town and do what you need to do, but there won't be any bigger pay check as a result of it.You might find it difficult to make plans with family or friends, because you won't know when you're working. Especially when you first start, because you'll be so new to things, you won't have a good feel of "i think they'll call me today" vs, "they probably won't" Even those feelings can be erroneous, and can trick a seasoned veteran. All in all , expect long work days (up to 16 hours) small flight pay(probably less than 8 hours a day, even for a 16 hour day) and the inability to setup a date on the weekends, or a ballgame, or a birthday party....For the price of $20,000 a Year, they get to own your tail....