i thought i answered this all ready..but i dont see any answers so apparantely i didnt. anyways. travelzoo.com is a great site for flights and hotels. it will find the cheapest flights on websites like orbitz.com and priceline.com and all the other ones. it will find you the cheapest stays. i have stayed in shitty hotels for like $60/night. hostels are cheap places to stay too!!! they range from $12/night and up. some websites you could check out are:
http://www.hostels.com/en/us.ny.ny.html

http://www.ny.com/hotels/budget.html

http://www.bootsnall.com/hostels/re/USA/New+York+Hostels.php

http://www.hostels.com/en/index.php

hope this helps. i always find cheap hotels to stay in. some of the hostel websites have cheaper hotels. or hotels that were a hostel at one point. it will have private rooms with just beds. you have to use a shared bathroom which kind of sucks but just bring sandals with you into the shower (who knows what people have) and travel sized toilet seat covers!! i’m such a clean freak that i dont like sharing bathrooms but you gotta do what you gotta do! and i would rather stay in a cheap hotel than waste more money that i could spend!! :-)

I stayed at the Doubletree Metropolitian for $99.00/night for Christmas day, the 26th, and 27th. After that, the price skyrocketed. Truthfully, $200/night in NYC isn’t expensive at all FOR THE CITY, especially at Christmas time. You can try naming your own price on Priceline.com, but you don’t want to go any lower than a 3* hotel.

Good luck! NYC at Christmas time is magical, though extremely crowded.