Run, don't walk over to the Blackmagic site and download Davinci Resolve lite version. It is insanely good and a very high end app, as it is mostly a colour grading solution, but the video editing features are fine for basic use. The new version is out any day now, and will have major new features added to its editing toolset...so good in fact that it will take a lot of market share from Premiere, Finalcut and Vegas. I have been using Vegas professionally for many years and will be moving over to it , once it is released. The free version is not hobbled much at all!
Other free options are Lightworks, which has been used on hundreds of feature films and Blender which has a basic non-linear editor:
The cut down version of Vegas is also quite nice along with Hitfilm express if you are looking for low priced basic editors.