Starting to loose track of all these versions of AutoCAD. I think there are two free ones now, one that works locally but you can store the documents in the cloud and they are testing one on Autodesk Labs that is entirely in the cloud. AutoCAD WS is also available as an app for the iPhone and iPad.
If you want something free that is remarkably close to using AutoCAD I recently had a play with Solidworks Draft Sight and found it very similar to AutoCAD with the bonus of working on a Mac too. While free it contains most of the 2D abilities in AutoCAD.
http://www.3ds.com/products/draftsight/