If you have an interview in NY and need to breeze in and breeze out, check out Roomorama which has listings for short term rentals. You can use it to look for an actual room, or if you are comfortable with this option, a couch surf. You can also pay online via PayPal and not worry about bringing lots of cash to a strange place. Listings are currently limited to NY, but the site does promise listings for Boston and Toronto.
You can combine this "cheaper" (really depends on listing and what you can afford) with a discount bus line, for true job seek economy travel.