if your friends invited you to come, then ask them if you were allowed to stay with them.
If you do, then you don't have to worry about paying for hotel, well, you are too young to book a hotel anyways.
the law is that you need to be at least 15 to fly by yourself unless you have a person who is over 18 years old that travels with you. or, i heard that if you paid extra to the airline company, then they escort you or something.
Well, getting a visa takes a long time unless you pay extra to get it done a lot sooner.
I mean, if your parents are approved of it, and would help you paying for stuff, i don't see why not.
Check orbitz for flights thats what i use.. :)
and it depends on when you fly out and fly back to cali.
between end of june to end of august the airfares are the most expensive.