I am not a big meat fan. My cooking skills are adequate and I will be living in a school apartment free, except for water and electricity charges. I am a teetotaller and a non-smoker. I will be in North China in a small city.

If I live as economically as I can, how much do you think I will spend in a month?

Cook at home, as a rule. Eat out now and again at a medium-sized 'Dongbei' Chinese restaurant. The dishes there are clean and tasty, generally speaking. Avoid dining out at small Chinese restaurants. You don't want a stomachache. Buy fried chicken legs with shanks if possible from Chinese takeaways. Eat them at home or on the street. Avoid western fast food restaurants as their dishes are expensive. Visit Chinese supermarkets as well as Walmart. Look for bargains. Avoid buying imported products that are too expensive. Buy their Chinese equivalents or do without. Visit wholesalers and street markets to buy staple foods, such as rice and potatoes in bulk at reduced prices.

Looks like you can survive with a full stomach without episodes of diarrhea on at most 1,000 RMB a month if you avoid unnecessary taxi journeys and the tempations of touring that involve overnight hotel stays.