Cheap hotels are everywhere. Most hotels in the city only run about ¥200 but they don't offer much more than the ¥80 joints near the train station. Remember, ask to look at the room before you agree to stay. Please, just say, "kan kan" and smile and check to see that you can really stay there.
If you really, really care about comfortable living, there's Golden Kue downtown at the intersection of Huai Hai Lu and Jie Fang Lu. Ask your taxi driver and give him a price and he'll take you somewhere decent, as a rule.
