Visa application for Russia

Hello, I am a foreign student in Harbin, China. Now, I want to go and attend conference in Russia. So, I would like to know following information when I go and apply one to Shenyang or may be from online (hopefully).
1. How much will need to pay for applying attendance type for Russia Conference (Academic conference and stay around 3 or 4 days)?
2. What kind of documents will need to apply for besides Passport, invitation letter of the conference. If personally go to Shenyang, before going, what kind of documents for there should be collected first?
3. Can I apply from online or in person to Shenyang? If possible, to save money and time, I like to apply from online or some agency of Harbin for applying one. If you know, please kindly let me know.
Thanks you so much in advance.