We flew into Newark--easy to get a cab at the cab station. The fare was $34.00 + tolls: $8.85 + cab's return tolls $8.85 + $1.00/bag + tip--about $60.00 for family of four. This was a NJ cab. On the return,we had a NYC cab and posting in cab gave fare to Newark as "meter rate + $10.00" (which totaled $38.00) + return tolls + tip. They (NYC cabs)can not charge for extra person or per bag. All the shuttle services charge $16.00+/person, so a cab is best if your group is more than three. Travel time to NYC
at 6pm on a Tues= 45 min, to Newark at 9:30am
on a Tues.=40 min.

The tunnel toll is $6 and you only pay when going into NY and not when leaving NY. The additional toll amount was for the NJ Turnpike. Was there any explanation as to why you paid the same amount of tolls for the drivers return considering there was no $6 return toll?

Actually, my husband was in the front seat and handled $$ transactions. The rates and rules at the NJ airport cab station were posted in an unreadable location inside the kiosk, and I don't remember seeing an explanation on the seat back. The NYC cab had the "Newark airport" charges plainly stated on the back of the front seat, but again, my husband had paid the cabbie before I had a chance to quietly explain that charges were differnt. I only post so others might be aware that there are clear "rules" the cabbie must follow, but he is not obligated to tell them to you, only to post them somewhere. I think we overpayed, but we knew everything in NY was expensive, and decided if we wanted to vacation there we wouldn't worry about every dollar.

The last time I took a cab from Newark airport, a dispatch person at the head of the line handed each passenger a yellow rate slip wiht their destination pencilled in and the allowable charge. I was going to an NJ destination, not NYC, but there was no mention of return tools (we went on the NJ Turnpike to reach my destination and I paid the toll - btw, the Turnpike toll from EWR to NYC extist is probably no nmore than $1.00 - $1.50 each way.

Don't be surprised about paying round-trip tolls . A NY cab going to NJ cannot legally pick up fares there (and vice versa) so the idea is for you to pay any tolls necessary for the cabbie to get back to his/her home territory.
What's annoying is when NY car services (which can pick up in both locations) charge the round trip toll as if they weren't going to get a fare back from Mewark airport to NYC.
I usually use car services that charge
about $35 plus tip plus round-trip tolls TO Newark, but as much as $50 (in the evening) +same tolls/tip because Newark cabs charge more than NYC.
I don't recommend the Supershuttle(unless perhaps it's for one person only) because when I did, I was told to wait for a shuttle going to my neighborhood (rather than get on one of the three ahead of it!) and then I ended up being the first person on/last person off on a trip that took over two hours and made 4 stops all over Manhattan. Definitely not worth the savings