Go to baggage level and go to the welcome center and they will give you different options. You can also take mass transit for much less but it will take a little bit more time.
I don't have the contact info because I didn't take that shuttle bus but you just have to walk downstairs from where you pick up you luggage at the carrosel and you'll see signs for the airbus that takes you to NYC so you should be able to ask then there...I know there is also the coach bus that charges 19 dollars to get to NYC from ewr too but I don't know if they go to jfk
Thanks! Your answer is awaiting moderation.