please am working here in qatar, want to sponsor visit visa for my brother for 30 days only.

Hi, bank statement of account is required, but there is no actual amount released by the embassy. As for the rate, it should be with at least USD100 per day.

thanks for your anwser but if i need to get a business one for my brother what can i do and who can help me., what will be the cost

For business F application, an invitation letter is required. The letter should state clearly applicant's name, position and passport number, applicant's company name, address and telephone number, purpose of visit, duration of stay and specific itinerary; You can also be his sponsor providing bank statement. But different embassy may have different requirements, he should better contact the embassy in Nigeria directly for details.