I've transcribed audio files part time for approximately a year, working for Rev.com. My typing speed is about 60 wpm. Audio must be good quality with one to two speakers. I charge $0.80 per audio minute. I can also do verbatim, time stamps, or other special requests, for an additional $0.02 per request. Turn around time is two days for projects 30 mins or less, four days for longer projects.