I had same problem when I was age 17. Well you can save money or at least find a friend who let you borrow their car.
I know parents can be pain the neck for stop you from what you wish to do. However if you live under their roof then just be suffer and deal with it until you move out. Find different job where you don't need transports.
I didn't get my first car until I was 23. Deal with it!
Take public transportation. It will be extremely difficult for you to get a job now before summer ends, since all the jobs for summer are already taken months ago (to start for training).
When any one is stuck and is literally screwed .... you think outside the box, I would suggest eating at jack in the box.