I'd recommend to install VirtualBox (https://www.virtualbox.org/wiki/Downloads), it's free and should take a couple of minutes.
Then download a VirtualBox image file at http://www.oracle.com/technetwork/community/developer-vm/index.html. It's free for development, but it's 4GB, so you'll need a good connection or some patience. It contains a fully set up Oracle database, no need to install or configure anything.
Oracle is resource hungry, so I wouldn't run the database server all the time, only when developing. Once you finished, you can stop the VirtualBox.