If you want a cheap flight from San Juan Puerto Rico to New York, you've got one airlines to choose from.
You can use the filters on your search to see more flights and find cheaper rates – New York has more than one airport. So if you don't need to fly into New York John F Kennedy Airport, it's worth checking your other options. The 2580 km flight usually takes about 4 hrs 5 mins.
If you're planning on going to New York during this time, you could take a look at other airport options. Or you could try to get a last-minute bargain.