So much of this depends on what is already provided. If you need to buy household items - sheets, towels, cutlery/chopsticks, pots/pans, plates, soap, toothpaste, toilet paper, brooms, mops etc etc you will end up spending a fair bit.
If the basics are there, and you plan on staying pretty much in walking distance you should be fine on 25-100Y per day. Here fancy fried rice - big plate (even when they say small), lots of vegetables is 3.5Y, 'hamburgers' (cai/rou jai mo) - 1.5Y, biaozi - really cheap per serving. So you can eat VERY cheaply - or you can go high-end and pay 100's.
But I would still plan on bringing 2x or 2.5x your monthly Chinese salary with you - you'll be here for 6 weeks without anything and you'll want to call home, use the internet, buy clothes that are right for the season etc etc.