Go to Tingxi. The first one: Shengzhi Township. The price seems to be around 200. Keep walking. The second one: Dida. 25-30. Keep walking. The third one: Cuifeng: The price is around 200.
There's another one. From Tongan to Maxiang. Pass the original Maxiang toll station. I forgot its name. It's on the roadside. The price is similar to that of the earth.