Budget accommodation in Shanghai and other cities.

I am arriving in shanghai from suzhou by either train or bus and staying there from 20th to 23th Dec. I do not intend to book any hotels in advance as i am not sure of my itin. I'd like to know is it easy to find some budget accomodation on arrival at the local train stations and bus stations.
Similiarly, is it alright to find accomodation on arrival at train/bus stations in Hangzhou, suzhou, wuxi in mid-Dec?