There are some hostels and pensions that are fairly cheap -- I have seen as low as 35 euro but most of those do not have a private bathroom. I stayed at the Victoria for about $115 a night and that is just a block from the host hotel. I dont know if it is still at that rate, but there are definitely reasonable places to stay; someone local may have more ideas. I spend a lot of time every year in hotel rooms so I do budget enough for swankier quarters like the Swissotel. I've done enough time in cheap hotels ;-)