For starters, you can download a copy of Reaper for free at www.reaper.fm
IF you like it you are asked to pay the $50 licence fee - this is optional but you really should do if you get into the software. The free version is uncrippled with no bugs or restrictions and it is genuinely as powerful as ProTools or Cubase/Nuendo (professional grade recording suite). Its got a steep learning curve but stick with it and you will be at industry standard in no time - tip, make sure you use the Reaper forums, they are way more helpful than the user manual!