Still not too bad. Parking off site (across the street from the airport at Avistar or Sky Park) is about $10-$14 a night, so if you get a room for a night and parking for $139 for the week that's pretty good.
I got a rate of 8.00 a day from EZ. We've parked there plenty of times and I trust them so spending the 135+ tax just to stay overnight when my parking bill could be 72ish! Ah heck we are on vacation right?
If you don't live more than a 1/2 hour from Newark Airport, why not use a door to door limo service? You can get good deals and some even offer $5 off coupons. Some even offer senior discounts. We live less then a 1/2 hour from Newark and appreciate the convenience of a comfortable limo ride to the airport and not have the hassle of driving to a weekly parking area, taking a shuttle bus to the airport with all of our luggage and doing the same thing upon our return. We pay around $43 one way plus tax, tip and toll. Traveling day is exhausting, so making your trip more comfortable is certainly worth the money.