I Need to Get There Please Answer ASAP?!?

Okay so me and my friend want to go on the Vans Warped Tour. Non of our parents can take us. So do we ride a bus, train, taxi, etc. What is our cheapest option? We also live in Grass Valley, CA and we are going to Wheatland, CA . We are 14. And we already have the hotel and that stuff figured out for the most part. Please Help! PS WHAT WOULD BE THE COST? Thank you!!