Advice needed on a decent speech-to-text software program.

It doesn’t have to be free, but it doesn’t need to be professional quality, either. I need something that I can mess around with and learn the ropes on. I also would rather pay a few bucks than deal with ads and stuff.

Suggestions?

[UPDATE: What comes with Windows is, on first look, horrible. I want to transcribe interviews, which means that I need a success rate that’s better than 40%. If that.]