What should I do to get China F visa or X visa & How much it cost ?

You can go through a travel agency appointed by Chinese embassy in Seoul with your ARC. Requirements are JW201 form and copy, admission notice and copy, a physical examination form and copy (it should also be done by an appointed hospital in Seoul, the list of these hospitals you can refer to http://kr.china-embassy.org/chn/lsqz/ls_qz/ls_qz_14/t258258.htm in Korean), application forms for China visa application (both V2011A and V2011B) with a photo stuck to it, in the application form, you should write down your living address, personal contact, and the name of the university in China. You re required to apply for a resident permit at local PSB with 30 days after entry. China Visa fee is 35,000 in Korean Won for a single entry. You need also pay extra service fee to the travel agency.