I think you've got two extremes here... helis will be about the most expensive and most difficult RC vehicle to get into, and RC cars will be about the cheapest and easiest to get into. I spent more on my simulator to learn to fly a heli than I did on my first RC car.

To get into a good nitro heli, you're going to shell out $1000+ easy. You're also going to have to join the AMA and a local RC flying club to have a safe place to fly it, and to get some help from more experienced guys, if there are any in your area.

If you're totally new to RC, I'd highly recommend an RC electric car first, they are the easiest and cheapest to get into. After that, you'll probably get addicted to RC, like I did, and move on to other RC vehicles that require more $$$ and have steeper learning curves.