SolidWorks is cool but the price tag is sometimes difficult to justify. Alibre Design looks like a great deal at $99. Based on this YouTube video, I'm impressed by the focus of the company. I think it is important to decide what your software will focus on doing well, rather than trying to make it all things to all people.
Update: After a little research, I decided the deal was too good to pass up. Alibre Design really does cover most of the commonly used functionality of SolidWorks or AutoDesk Inventor. I suspect they are having the promotion because the next major version of the software is due to be released soon. Serious users will pay full price for the new version so it's a clever promotional strategy.