Reaper offers nearly all the features and flexibility, if not the ease of use or visual appeal, of powerhouse digital audio workstations like Pro Tools, at a fraction of the cost.
If you're looking to get started in podcasting or recording music, it's tough to go wrong with Audacity. A powerful, free, open-source audio editor that's been available for years, Audacity is still the go-to choice for quick-and-dirty audio work.