I Want to Start My Own Business, but how do I get the funding?

I am 18 years old and have an amazing idea for a business that would be very successful, but I do not know how I would get ALL the funds I need. When looking at the costs of leasing a building, it seems that buying a building would be a better choice. So along with the building, I have all the materials I would need to purchase and I feel like the amount of money I need is impossible to come across without winning the lotto, yet tons of people have started their own business. So PLEASE, how do I get the financial part started so I can get this show on the road?? Thanks So Much! =]