Sorry, was away from work for almost 3 days...
Frankly speaking I don't know hotel prices here

Usually on business trips I have hotel pre-ordered and don't pay for it myself, or have the honor to be someone's guest (many thanks to my Friends who are kind enough to host me).
Here is the first site in English with hotel adresses I have found:
http://www.admcity.nnov.ru/english/hotels.eng.htmlAnd I don't even remember the name of the hotel where I stayed in Nizhniy (Gorkiy) in 1999

I think that you'll easily find decent hotel for about 50 Euros daily or less. By "decent" I mean the quality that satisfied Grendel and friends on their trip to Karelia in July.