You can get 15-day and 30-day demos, 6-month and 12-month versions, and completely free CAD, both 2D and 3D. Heck, you can get Inventor for free, legitimately: all you need is an email address that ends with .edu and Autodesk'll send it to you.
All this free software from first and second tier CAD vendors is having a negative effect on third tier vendors. The ceo of one tells me:
All the free giveaways of software from heavyweights such as UGS, SolidWorks, Think3, Google, Bentley, and others have an impact on our sales.