For single entry visa, the price is HKD210 and need 3 working days to process. The waiting time is short (I used 15 min in Kwun Tong branch) as not many people need to apply China Visa. 所需文件 :
1. 有效的護照或旅行證件正本
2. 交近期二吋半身正面免冠照片一張
3. 填寫“簽證申請表”一張並簽名
4. 申請人如無香港入境印章(用香港身份證入境人仕),需帶同香港身份證辦理簽證。
For details, pls visit below link:
http://www.ctshk.com/zhengjian/china.htm