Translating video/audio files into usable and valuable texts is something that different industries require, most notably legal proceedings, academic lectures and medical prescriptions are transcribed into texts and if you go online and search for the fee that you would have to pay to transcribe a document you would get confused by the contrasting amounts that you would come across, but as someone who has availed the services multiple I am well aware of which service provider is charging the right amount and which one is asking for excessive money, there are a few factors which decide whether you should pay the excess amount or not. At https://www.espressotranslations.com/cost-of-transcription-services/ you can learn all about what these factors and why certified translation is important and despite of the charges why people are always willing to spend extra to get certified translation.
When you want a transcript from a service provider you are generally look at a cost of $0.10 to $0.50 per word but that could change depending on a lot of things, you have the option to hire a freelancer which is surely the cheaper option and on the other hand if you hand the task to an agency then you would have to spend big, so there is standard rate which applies to all but it is situational, the best thing to do would be get the quotes and rates and compare it with similar alternatives, but whatever you do just make sure that price is not the only deciding factor and you are taking the experience of the service provider in consideration as well.
If the documents holds legal value and it can bear legal consequences then it is better that you avoid getting services from an inexperienced freelancer, rather you must opt for an agency.