Is WonderShare's video editor a viable alternative to Camtasia Studio?
If you are looking for software for windows then:

.Lightworks (free but you need an account)

.Jahashaka

.If you do not want to use either of those, use Windows Live, Blender, slowmoVideo, and GoPro Studio together in your workflow.
  Typically what I do is import the file using GoPro studio(which can be used on most video formats) and color correct the video, then either using GoPro studio or slowmoVideo I add slow motion effects if needed, and Blender can be use to add CG (something I've never done) or maybe camera movement. The final edit of clips, i.e syncing it to music, etc. is done in Windows Live Movie Maker.

If you are uploading to YouTube I highly recomend you check out GoPro studio.