If you want a cheap flight from San Diego to New York, you've got one airlines to choose from.
Make sure you use the search options above to search for flights to other airports in New York, not just New York La Guardia Airport. The more options you look at, the better your chance of finding a cheap deal. Just so you know, the flight typically takes 8 hrs.
During this peak season, hotel and holiday prices often increase too, so it's best to book early. Or you could keep your fingers crossed and hold out for a last-minute deal.