Are there free programs that will decrease speed on an audio file but not the pitch?

Try GoldWave.

I would give Audacity a try. It is free and open source.

http://www.audacityteam.org/

Windows Media Player

Realplayer is free (but has some annoying nags trying to get you to user their cloud service and upgrade to the paid version).

Thanks. I will try them out and report back.

@johnpowell Audacity works well, and will be good enough for me, thanks. It requires a conversion from M4A to mp3, and the sound quality on slow down isn’t quite as good as Amazing Slow Downer, but it’s good enough for practicing, and it’s free. Thanks for the tip!

I really love Amazing Slow Downer by Roni Music.

Not only slowing down, but also export, analyzing pitch, remove vocals, etc.

Useful if you want to know song’s detail or if you have any instruments to work on

Thanks. I’ve used that too.