Travelling to China

Next year, I want to go for a month and visit Chengdu and the Sichuan region. I already have a place where i want to stay, but i don't know when are the cheapest times to go. I am 17 now and i don't have that much money... Could you also tell me if a budget of around 1000 - 1100 euros is good only for food, commuting, paying for museums and others? I plan to eat street food, like the locals, and use the metro. Please feel free to give me all type of tips for visiting this part of China! Thank you