Demo / Cheap Sound Editing Program

Aloha,

I'm interested in messing with pre-existing clips, and some voice overs for several different uses. The problem, every program I find in demo for is a MIDI mixer (Not even a MIDI mapper). But I'm trying to some things I used to do with sound recorder in Windows. Mainly split tracks (to remove a section, compine several sound files, reverse, increase/decrease volume, add reverb, or mix two sounds together so they sound overlapping.

Any help you could render would be greatly appreciated.

TEG