You want to produce an audiobook, audio course, or some other recording, and in need of some pro-caliber software (and its feature set), but those cost an arm and a leg. Well then, you’re in luck—there’s Audacity.
Audacity is a multi-track audio recorder and editor, rich in features and capabilities. And it’s totally free. That something this capable costs nothing is mind-blowing; it’s open source, and developed and maintained by volunteers. Throw in the fact that it’s available on multiple platforms (Windows, Mac, Linux) puts it squarely in amazeballs territory, as if it weren’t already.
Relatively easy to use, but take that with a grain of salt. Of course, if you’ve never played with this kind of application before, expect a learning curve.