How much money do you guys have currently?
www.firstnemo.org has some great resources for rookie teams. I would say that about 10000 dollars would be the minimum for a season. I would be glad to help you guys. Do you guys have a mentor yet? if not find a teacher or parent or engineer to do it. Mentors are an absolutely invaluble resource. Try to find sponsors in your area by sending a handout (like the one listed under the resources section of the NEMO website under the sponsors section with different levels of sponsors they can be) and give them to every business in your area.
I hope this helped, vivek
p.s. pm or email me, I would love to talk to you about stuff.
last year we built mostly in a parents basement and a school room after school that was used as an engineering subject teaching room.