Flying into New York (LGA and JFK); take the bus and train into Manhattan for as low as $4 or $7!

I lived in New York over the summer and as most people we come to the City, particularly Manhattan know, everything is expensive.
 
When I was younger, I used to stress a lot about paying for a taxi from JFK and Laguardia.  Taxi's into the city were notoriously expensive and even made more so when you are a student.  During the summer, I was able to take the bus from LGA to Penn Station, Grand Central Station, Port Authority or mid-town Manhattan hotels for a mere $12 one-way and $21 for round-trip.  www.newyorkairportservice.  The M60 into Astoria, New York http://www.mta.info/nyct/bus/schedule/manh/m060cur.pdf where I used to live is still $2, and for another $2 you can get on the New York subway system at Columbus Circle. Into the city for $4! The bus and subway trains are air-conditioned. (The terminals are unfortunately not.)

At JFK, the airtrain takes me to anywhere in New York City for a direct cross country flight for a mere $7.  That is $5 for the airtrain and $2 for the subway.  http://www.panynj.gov/airports/jfk-airtrain.html Similarly going from the City to JFK is also $7.
There are much lower cost than the $50 cab rides that used to take into the city, and much less stressful since I am not watching the meter all the time.