Christopher's School Trip

Ever since I can remember, I have wanted to travel.  I have wanted to see new things, experience the world and not be stuck in one spot my entire life.  That was even before I knew how big and amazing the world really is.  Since then, that itching feeling to travel has only grown.  This is a once in a lifetime trip with my school to Costa Rica and not only will I get to travel and see new things, I get to learn about Costa Rica and nature.  I would like to make my career in doing something with nature so this would help me determine if I'm following the right path.  I need help though.... to go it costs approximately $3000 without buying a passport and all that good stuff.  I have been able to collect only $555 through various jobs and saving any money that I get through my birthday and other special occasions.  Since I just turned 15 I haven't been able to get a part time job.  My family can only help a finite amount too.  Since my Dad is on disability and cannot work, and my Mom works at Walmart, money is very tight.   If I had more time to save up the money I might have been able to pull it off but I don't.  I am asking for your help because I am out of options.  Please help me go on this once in a lifetime trip.  Thank you.