how much should i pay for BUSINESS type visa? and can i apply through internet?

Hi,
i am going to participate in an international forum organized by UNESCO in china . i should apply for a business visa .due to my tight schedule , it is quite hard for me to go to Busan for getting my visa. therefore i am asking ,can i apply through the internet ? by email .or should i go to Busan ? and how much i need to pay for my visa ? i will stay there for 4 days, though.
thank you very much