All the information you are looking for is right here BATF FAQ
The application fee is $200. You must have a business and pass all the background checks. Expect to wait up to 8 months before they come visit you at your place of business.
Application: ATF Form 7 (5310.12)
Type 01: DEALER in firearms other than destructive devices.
Fee: $200.00 for the first three years. $90.00 on renewal.