Depends on how much you work, whether you work day or night, your lease rate, whether you own the car, whether you own the medallion, and how good you are.
Just starting out days figure 100, until you get better, then like 130. Maybe more if you find an owner who wants to work nights, and gives you days for like 100 less than the garage rate- which is an extra 20 in your pocket every day.
Also, make time, not money. If the person wants to go over the free bridge, recommend the toll. If he doesn't want to pay the toll, pay it anyway, and eat it. The $4 you pay will be quickly made up in the 1/2 you save, and oftentimes the person will relent and offer to pay since it turns out the same. But never force it on them, just eat the toll. Also, if they are going to Path train and its late- offer to take them to Jersey. They might not realize you can go there, the worst they can do is say no. About 1/4 of the time they say yes, so you get a long ride with cheap gas. Same goes to Grand Central or LIRR late at night- they might be going to Westchester or LI, and if its slow, that is a great ride. Even if you give them a discount, you come out ahead with no traffic. Always be nice. Always. Not worth the stupid ticket that they will hit you with otherwise. Don't take more than 5- not worth the ticket, the hassle, or the attitude. They say they will take care of you- they never do. Good luck.
Antolin