I´m a qualified nanny and the cost depends on a few things:
1. how many children
2. their ages
3. what qualifications the nanny has (the more qualified the more expensive)
4. live in or live out (live in Nanny’s (Au-pairs, are cheaper because you give them room and food free)
5. travel expenses have to be given to the nanny (so if you pick a nanny that lives further she will cost more)
6. what you want the nanny to do (school runs, cooking, house cleaning)

if you want the nanny to look after 2 children and clean only the children’s rooms, cook them meals and do the school runs i would charge you 10dollars/hour. also nanny´s now by law have to have holiday time (paid) and sick days. (well in England you do) but its quite easy to find a nanny that doesn’t require these things, personally i never asked for extra money for travel as who can really afford that i already got more than min wage so i wasn’t going to ask for more, I’m sure you will find a nanny like that, also if she asks you for loads of extras, that you can see aren’t 100% fair (i know a lot of nannies that try this) you have to wonder if she is really in this job because she loves children or because of the pay. i wouldn’t go through any agency either they rip you off and i don’t trust them. i always go through free ad´s online and i always find nice families.
good luck in your search

edit: Nic is right Greataupair.com i a good site though im pretty sure the parents have to pay.
also try:
aupair-world.net

this is the FREE site i always use

it comes in English and Spanish and i just checked it does NY/NJ areas

I was a live in nanny in the same area (not from an agency but with experience). I made $300-400 per week for 2 children full time ($300 was the agreement but they offered more when I took on extra hours/duties).

For the hours you are seeking – if they had an hour ‘break’ at some point – minimum wage would equal $340 per week, assuming you can find a live out nanny in the area who can afford and is willing to work for minimum wage.

You’re right that nannies from agencies cost more as the agencies add on an upfront fee and a percentage of each nanny’s pay per week (in many cases).

My sister was a long term nanny for a family in Pennsylvania and she made (at their offer) $600 per week.

Now that I am a parent I have no idea how families afford that kind of money (or child care). I have been a stay at home mom in part for this very reason! (I also really love kids – especially my own.)

I’m not sure what the costs are for the parents but I used and posted a profile through them when I was looking for a position. That’s how the family found me. It’s a very popular website in the tristate area so you should be able to find all kinds of nannies and price ranges.

Good luck to you!

At least 10 dollars an hour.

I live in Canada and i’m a Nanny. I do $1000/month Full Time. Everybody comes to me because i’m professional and at low cost!

My friend pays $1200 a month for a ft nanny, not a live in.