Cab fare depends on where in NJ they are going. Figure anywhere from $80 on up. They can take a cab to anywhere in Manhattan for a flat rate $45+tolls+tip, maximum of four persons. NYAS express buses leave from all terminals to Grand Central Station, Port Authority Bus Terminal and Penn Station, cost is $15 per person. LIRR and E or J subways from Jamaica Station or A subway from Howard Beach Station, both reached by AirTrain, will take them to Manhattan.
Cab fare depends on where in