Hi Marius,
I am a local in Chengdu.Your budget 800 RMB a week is same as my salary per week.I think you would enjoy in chengdu at your ease.Chengdu living cost is mainly on house rent,if this cost is zero,you can save a lot.And more if you usually cook by yourselves, it is save more.Sichuan is a agricuture province,which have abundant of meat and vegetables,eatting is so nice!
It is up to your expenses ways!
Welcome to Chengdu!!