Just be aware that Casting Words (on mturk) has a grading system. One of the things you're graded on is how many inaudibles you have in the transcript. If the person doing the grading doesn't actually listen to the audio to see that a recording is especially bad quality, you may be assigned a poor grade that you don't really deserve. Too many of those and you can no longer work for CW.
When was doing work for CW there were a couple of really, really bad files that I took and was given a poor grade on. One of them was so full of RF interference that significant portions of the audio were almost completely washed out. It was given to another transciber to "improve" and when I looked at the "improved" transcript there were whole portions of it that I could only assume had been made up out of whole cloth because I didn't hear anything like that in the file I was listening to. That's when I stopped taking work from them.
Additionally, CW generally does not want verbatim or even intelligent verbatim. They want their work transcribed strictly for readability and edited as you go for grammar. Be sure you read their guidelines carefully if you decide to go that route.