Christ man I was offering an example of a billion dollor amount. I can't do the math without round figures. You make 15% selling toothpaste? Good! Welcome to private sector Space exploration.
I'm not trying to be argumentative and I agree with your main premise; the space shuttle is inefficient way to get payloads into space.
However, I am saying that there is no economical reason to go to Mars. If it doesn't make good business sense, it probably won't happen in the private sector. Private companies can build the hardware but only the government can absorb the costs involved.