They programmes are I believe, all wave editors.
Sound forge is great for wave editing though I don't think it's free.
Sometimes you can download free copies of older versions.
I think Audacity grew in popularity because it let you record from the internet?
You really need multi-track software for music recording...so that you can record say, uke on one track, vocals on the other and drums or bass on the others and then mix them all to the levels you want.
Sound recording is as much an art as playing an instrument....and using PC (or MAC) software is another whole art...you could easily do a 3yr degree course on most of the popular pieces of software....and still know less that 1/2 of what these things are capable of!
It can be real fun when you're getting into it....whole days can just slip past as you try and record one song!
A good mic' is very important if you want pro' level stuff...you can kinda "fix it in the mix"....but it's much better to record it properly in the first place.
My opinion is to record everything simply...if the songs or your playing are good enough then someone else will pay for pro's to record it....no matter how good you think your home recorded stuff is, 90% of record co's will get you to re-record it their way...which can be really frustrating if you just put months into recording a song the way you like.
It took me 3 months to record 15 songs for an album, working pretty full out..
Then there is MIXING every track....taking out any wee imperfections and getting the volumes right...
Then there is MASTERING which is basically trying to get 15 songs to play back at the same volume and to sound like an album.
Phew...I still say it's just best to hit "Rccord" on sound recorder on the laptop and shout into the mic for 3 min!