I don't do this myself, but wanted to suggest the possibility of medical or legal transcription. I think many community colleges offer classes on this to learn the lingo, etc.
At my old job (for the Judiciary), we would have to order transcripts of legal hearings. We would send the transcriber the tape, but the billing part was dealt with directly with the attorney or the person who was arrested. I think our transcriber charged something like $3/per page, and she would require a deposit up front (she did have a couple of problems collecting the money, but I think for the most part people paid her in a timely manner).