this was asked 2 weeks ago & lots of answers advice here
viewtopic.php?f=5&t=290861There is details about a coupon for Carmel in that thread as well.
Carmel Limo, Uber, all the 7, regular taxi & air train (being the cheapest if theres 2 or 3 of you - that takes you to Penn Station)
I used Carmel Limo & it was the same price as the Taxi - Taxi to JFK is fixed price, this is advertised on the side of the door.
This cost me $70 (from Upper West Side) which included tolls & tip ($52 basic fare + tolls).