I really can't add a lot to what Iceman has said because, frankly, I'm not qualified to be his pool boy.
I started with $10 free on Royal Vegas (Prima) and $10 free from Pacific. I built this up to around $2K playing fixed limit. I've never put a dime into a poker site that wasn't someone else's dime. There was a happy result from this. I learned how to play as it took forever to take that $20 to $200, which is what you need to play anything of significance. It took a LONG time, and like ice, I pretty much went through everything in that time. A year later, and I'm just barely a decent player.
Limit is more guaranteed. (If I'd stayed playing FL, I'd be much richer.) It's also more boring. NL is more fun, but the swings will make a new player insane, I think. SNGs are my cash flow, now, but I wouldn't recommend them for someone just starting out. Play limit poker until you are well grounded, then look around at other options.
As for making $1000/mo.? Uh, well, good luck. A very good limit player is happy making 3BB/hr. At $1/$2, which you should not be playing, that's $6/hr. Believe me, that's not easy to do. Playing 4 tables, I think I usually got somewhere around $8/hr consistenly. Not much of a part time job, unless you consider sitting for hours in a small room staring at a computer screen in your underwear a good job.
Good luck. It's a helluva ride, an endless educational process, and an obsession no one else understands. (Esp your wife.)
CJ
"Are the players better as the stakes go up? It's not an exam; it's a buyin." Barry Tanenbaum