You can download it for free on the web.
From http://www.orafaq.com/wiki/Oracle_Licensing:
A license is the "right to use" (RTU) the software and
not the software itself. If you have a license, you can
obtain a copy of the software through whatever means -
order, download, use the CDs from your last project, etc.
Please note that Oracle doesn't use software keys. You can
just install the software and use it. It is up to you and
your consciences to license the software before using it.