Sound Effects Creation Software

Can anyone recommend some good software for creating sound effects for videogames? Low-fi could work well.

Bonus points for naming free or shareware software…

Ah, thanks! That’s perfect.

I just downloaded an OS X one that looks pretty much identical:

In a game I made that was meant to be retro (but not sfxr retro) I used sounds from and then downsampled and messed around with them using audacity. Audacity could be a pain to use, and had a habit of sometimes bulking tiny wavs up to huge ones by adding silence at the end; I actually ended up using the windows sound recorder for some of the downsampling.