They're going for between $800 and $2,000 at present. But don't pay for them; they're suppose to be free. I got this note just a moment ago:
Tickets are obtained through the office of your Senator or Congressman/woman. They are FREE... and very difficult to get.
As posted the following site (and many other sites):
http://travel.latimes.com/daily-deal-blog/index.php/ obama-inauguration-t-3224/
“Any website or ticket broker claiming that they have inaugural tickets is simply not telling the truth,” Howard Gantman, staff director for the (inaugural) committee, said in a release. “Tickets for the swearing-in of President-elect are all provided through members of Congress, and the President-elect and Vice President-elect through the Presidential Inaugural Committee. We urge the public to view any offers of tickets for sale with great skepticism.”
This goes for parade tickets also.