Most people have no clue what's included in the actual transcription of an audio file. After that you can bargain for lower transcription rates once you detect things you can do to make lifer simpler for the transcription service. What appears "acceptable" to you may be horrifying to some transcriptionist. Background noise, record in a vehicle with the windows down, loud restaurants, even the tv or radio on when recording could make the sound hard to transcribe.Be mindful of the noise that you don't think twice about, but it'll be picked up on your recording.
When recording a large groups, instruct the speakers to speak one at a time and present themselves. This makes it more easy for the transcription rates to decipher each individual speaking and there will be less [inaudibles] when most people are talking over each other. Many transcriptionists, have applications but some don't. Some will charge extra for converting video files to sound. Check with your transcription service if possible,, and first convert the file yourself to save some cash.
There's nothing worse than expecting a file back the following day and the transcription service will not have it ready for a "few days." Be clear when placing your order if you need it back. This avoids frustration on your end and the transcriptionist rushing to complete your transcript. Keep in mind most "Hurry" jobs will cost more.