Karts are also pretty expensive as well. My friends and I were looking into it last year. The tires are $100+ each. Engine rebuild on almost once every year. Brake pads and rotors cost about the same as cars. The only difference is the space and initial investment. That's about it.
I agree. If you want to go open wheel. Kart is the way to go. If you are looking for touring cars, I suggest you start with Spec series. Like Spec Miata or Spec Neon.
'03 BMW X5
'03 BMW ///M3