Halloween party ideas, please help!?

Me and my friends are throwing a huge halloween party at the neighbor hood clubhouse and we need some ideas on what to do! Most ppl will be 14-15 years old and we also need ideas for TONS of decorations. we already have a lot but were gonna need more but we cant spend too much money so got any ideas? think we can make some stuff? got any ideas we can do at the party? thanks!