What would be a job that would allow a pre-teen to get money? And im looking for something better than babysit?

my friend wants to go on this five-day school field trip to Catalina Island, but it costs $355 dollars! Her parents say that she has to pay for half of it, and that deadline is Dec.4,08!! Please give me some ideas!! I don't want to go to catalina without my best friend!! :(