which type of visa should I apply? how much will it cost me?

You should apply for a M type for your business trip. It costs around 8000 Naira. Its address is Plot 161A, Idejo Street, P.O.71510, Victoria Island. To apply for M type, it requires your passport, finished application form, a recent six months passport photo, invitation letter from your business Chinese partner and invitation letter from duly authorized Chinese unit, a formal introduction letter from your company, your company's business license copy and your bank statement that proves you have at least 4 million Naira in your account.