Quote from the Opera ASA webpage:
Yes, you read that right. We'll say it again: Opera is free. There are no more ads, no more registration, and there has been no better time to try the best browser on the planet. From this point forward, you will be able to download the full Opera browser for free from the standard download page. We hope you are as excited as us about this new release.
If you would like to help in the distribution process, we would appreciate if you could download the install files via our official Opera torrent, and seed the file once your download completes. For more information on BitTorrent technology, please see our BitTorrent Resource Page.
As a side note, if the "O" logo under this post has a gray or light blue background, your web browser does not show PNG-24 images properly.