But you realize that taking a NJT train to NY Penn will set you back $12.50 EACH WAY? If time is of no concern, you could take the 62 bus to Newark Penn station ($1.50) and then take the PATH train ($2.25). Of course, this is only recommended during daytime if you have enough time. You may also need to take the airtrain from P4 to one of the terminals (free of charge) to take the bus.

http://www.njtransit.com/pdf/bus/T0062.pdf