Mort's estimate on budget is right on..
Last year we were more affiliated with the elementary school, and we sold bake goods at the various after school gatherings, as long as soliciting support from our local businesses.
http://www.lego-leopards.org/index_files/Page2140.htm
This year, the three coaches all had kids that moved to middle school, so we made up the team from our siblings, and were less motivated to do fund raising,
so we split the costs 4 ways and the families paid.
Edit: Forgot, also check out the unofficial coaches manual from FLL-Freak's website,
http://www.fll-freak.com/ it is packed full of excellent first hand suggestions.
Good Luck!