I got The Paramount on Orbitz for about 150 a night-it was during the summer, which is also a busier season.
"The sexual energy between the mother and son really concerns me!"-random woman behind me at Next to Normal
"I want to meet him after and bang him!"-random woman who exposed her breasts at Rock of Ages, referring to James Carpinello
Summer is not a busier season than holiday season in Manhattan. Any night from Thanksgiving til after New Year's is going to be more expensive than a summer stay. Prices skyrocketed this fall at all decent hotels in the city, and holiday season is going to see them even higher.
Last weekend I stayed at the Hotel Bellclaire on W 77th at Broadway....it is super clean, very friendly and paid 169/night. They have everything from economy (shared bathroom) rooms to doubles. It is 2 blocks away from a subway station that will let you take the 1 train into Times Square. High recommendation for this amazing jewel.
I stayed at the Millenium Broadway (11/10-11/12) for $339 per night that I got off of Priceline. I know there are some deals out there for December, so you might luck out. Especially right now, but as I found out, it depends on when you check in. Friday and Saturday nights are killers.
December is peak season, hotel rates-wise. Why not try some East Side hotels which are near the crosstown (49th-50th streets) bus routes? It is an easy walk to and from the theaters.