There is nowhere near enough information there to answer your question. You need to do a financial analysis of what you need to start up and how much each thing you need costs: are you starting a league, or just a team? What other teams is your team going to play? Is there an established league already with other teams? Ask them how much it costs to start. Does the league have registration fees? Are you buying equipment and uniforms? Used or new? Are you going to need any paid staff? Do you need to rent a field to practice on, or can you get one for free? Do you need a bus for transport? How much and what type of insurance do you need/want? What does semi adult mean? Touch or tackle? Where are you planning on getting the money?A consultant would want to sit with you while you go into excruciating detail about what you are looking for, what your expectations are, what your plan is, what you want to get out of this endeavor, and then put together a plan to accomplish your goals, including a financial plan. Without knowing a lot more detail about your expectations and your idea, it would be impossible to come up with a number.
It would depend on your state.Try going to IRS.govYou will need to fill out the 501(c)(3) application and mail it into your local IRS..It will cost as low as $288 to $500 to file this and get everything started..Here is a website that might help..http://www.501c3.org/501c3_process.html
