An average meal won't cost you much. A Big Mac Meal at Mcdonald's costs only about 15 RMB, which is equivalent to about US$1.50. I don't exactly know how much a meal somewhere else will cost, but even if you visit a restaurant, it's rather cheap compared to your own country. Public transport is rather cheap though. But if you don't speak or read Chinese it's going to be quite a problem for you. Bring along a friend who can speak Chinese.

Just don't try to be a smart aleck and eat the food served at roadside stalls. That's when you're asking for it. As long as you visit reputable restaurants or hotels, you're safe. And it's not that dirty, really. The toilets do smell a little funny, but hey, i come from Singapore, and if i can take it, so can you.