Like mentioned earlier, what is your goal with the sport for right now? If you are just now learning about the sport, I would go to the track and see what is offered in your area. New Jersey Motorsports Park is the biggest facility that is close to you. I would also check out Mike Doty Racing to see what used packages he may have for you, that are ready to go.
Your first question however is, what class and engine do you want to race?