Read along in the comments:
The first draft, which the CBO scored without a public plan included, came in at over $1 trillion over 10 years. It had holes in it for a public plan, though.
Now that the holes have been filled in, the CBO has scored the whole thing cheaper, at $600 billion over ten years (small potatoes next to the $750 billion in TARP money in less than one year). So, with a public plan added, health care is actually LESS expensive.
So Joe Lieberman, Mr. "fiscal responsibility" who says he won’t support a public plan because it’s a "cost we can’t take on," can officially go Cheney himself.
[T]oday’s CBO score is low in part because we’ve made some of the policy worse. It would be a good thing for 15 million Americans to move from employer-based insurance to the exchanges. It would be a good thing for 60 million Americans to do so. But no one knows how to pass that bill. So here we are.