At 17, you cannot drive a rental car, much less rent one on your own. Since you are not a legal adult, you cannot sign the rental contract.
Look into Greyhound and see if it serves the cities you need.
Look at skyscanner.net and statravel.com they usually have the best flight deals.
Greyhound is pretty cheap to travel but it does get boring since a bus takes longer than a normal car. Look at greyhound.com
When I was your age I would travel with greyhound to visit my dad in another state since it was more convenient. Compare those options and see what works best for you. Consider that you'll be having to pay for food while you travel on bus or luggage check if you fly.
Good luck!
For rented a car you can check all about car rental services. You can get car on lease with cheapest cost from here.
I would say you rent a car with unlimited Mileage from firstclickcarhire.com
Thanks