A prospective international student must obtain a student visa to enter Korea. Please refer the following webpage. (Study in Korea).
A student may live at a dormitory or an off-campus apartment. Monthly rents for off-campus apartments vary depending on their locations and conditions. Also, a security deposit (usually more than $5,000 and refundable) is required. As for the dorm, the 3 month rent should be paid in advance. Rent fee includes meal as well. The cost is about $400 per month. Please refer the following webpage (Dormitory of HBNU).
A prospective international student may get information from the following webpages.