While I agree with your comment about learning more by doing the work yourself, you don't need to be a billionaire to acquire one of these. Yes, they are expensive. A typical pro-level WRC spec WRX STI rally car from Vermont SportsCar goes for about $600k. They are actually very reliable though. And thats a bargain compared to just about any modern hypercar.

Rally cars also must be street legal because they are driven on public roads between stages.