What will the cost of this Sweet Sixteen be?

I have my heart set on having a sweet sixteen. Money is a little tight in my family right now but if I want one bad enough my parents will manage. I am willing to get a job but that's besides the point. Having one with a friend is what I prefrebrely want. That may not happen. I plan on inviting around 100 people including family. With buffet food in a nice but not very high end banquet. There will be just a sheetcake so cake money is not an issue. How much do you think getting a: dress, banquet, custom shirts(party favors), center pieces, accesories, etc. etc. will cost in all. and if you have any input? thanks so much!