Well, it's hard to say. Every time when it's around the festival, the accommadation fee in Harbin will increase a lot. But you may have a try, maybe those hotels around the universities has cheap rooms.
The Ice and Snow Festival will be officially started on 2011/01/05, so it's a little earlier now. However, the skiing resorts there have been opened.
Ice festival shows? Do you mean the Snow Sculpture Art Exposition, it's rmb150. BTW, there are detailed schedule of the activities held this year on the bottom of this page, you may have a look there.