Where to purchase tickets to New York would depend on the type of travel desired. For airline tickets sites like Expedia and TripAdvisor allow the customers to locate deals from all over the US. For rail and bus tickets, Amtrak have some seat sales that would make traveling to New York more affordable.
I have heard the sooner you buy the tickets in advance the cheaper your can get the tickets. But I do know of a cheap website to buy airline tickets online at: www.orbitz.com.
You can purchase New York Jets tickets on the official New York Jets webpage. If they are sold out, you can check Stub Hub or Craigslist for anyone who is reselling their tickets.
One can buy cheap Eurorail tickets from the official website of EURail. One can also buy cheap Eurorail tickets from websites like Rail Europe, Rick Steves and Travel student.
You could find some good tickets to sports events in New York online through Ticket Master at good prices.
There are many online resources one has to purchase New York Islanders tickets. Ticketmaster regularly has tickets available for sale as does Stub Hub. Currently there are no tickets available as the season just ended.
There are a lot of places where cheap group airline tickets are available online. airgorilla.com and travelocity.com are just a couple of good locations to get cheap airline tickets.
You can buy cheap travel tickets from various discount sites on the internet. Also, many travel agents will give discounts to new customers and even calling the airline directly can save you money, because they need to fill seats.
tickmaster.com or ticketmaster.ca depending if you want tickets in Canada or the USA and they are only cheap if you want crappy seats
Move to NYC
On the internet.
Popular travel websites such as TravelZoo.com, Expedia.com, and CheapTickets.com are excellent resources for discounted airfare. CheapTickets.com is currently offering round-trip tickets from New York to Cancun, Mexico for around $350.00! You can purchase cheap airline tickets to Mexico at several different websites. Hotwire.com offers discounted airline tickets and cheapflights.com allows you view and compare flight costs at multiple websites at once.
I have bought really cheap plane tickets on Orbitz.com. I would definitely recommend their services.