How dependable can the income of a medical transcriptionist be?

I'm looking into an online course that can help me become a medical transcriptionist in about 6 months. My husband and I wanted to know before we invest the time and money if it is even worth it! We have a little boy getting ready to start school and would like to have a job where I can make my own hours...work at home...pick him up...drop him off...actually talk to the teachers and be somewhat involved...we also hope to expand our family soon and thought this might be the way to go to keep our new baby from having to go to daycare. How much do these types of jobs usually make?...And how can I tell if the online course I choose is legit?