If you have a positive win rate, you need to really pat yourself on the back. Almost all poker players lose money over time. We don’t want to discourage you here if you are not a winning player yet, as it really isn’t that hard at all to master the game enough to start making money from it. However the fact remains that most players do not.
Most winning poker players average between 1 and 4 big blinds per 100 hands, or in other words up to 4bb/100. This doesn’t mean that you are limited to that though, and the better you are, and the worse they are, the more you will make.

Naturally, higher win rates are possible at the lower stakes, since the players there tend to be weaker on average. As you move up the stakes, you will find that your win rate will tend to go down, so while it’s not uncommon for instance to see a good player with 10 bb/100 at a lower stake, it becomes a lot tougher to do this at the higher stakes.
However, keep in mind that as the stakes rise, the value of a big blind also goes up, so you will typically see your big blind win rate go down but your profit per hour go up. Of course, if you hit a point where you end up losing money, that’s a negative win rate, and at that point it is usually best to move back down until you are more ready for the tougher stake.
So as far as what’s reasonable for you at your given stake and point in your poker development, we can say that any positive win rate is good, 5 bb/100 is quite good, and over that is very good indeed.
So if you have a winrate of 5bb/100 in $1/$2 NL, you are winning $10 for every 100 hands you play. We can assume that you can play 60 hands an hour on average in full ring games, so by playing 4 tables at the same time it will be 240 hands per hour and $24 profit. Let’s go further and assume you are playing 5 hours per day – your daily profit will be $120 and on avarage you will win $3600 per month.