We all will have a different answer because we all have different experiences.

In my experience, I know that I can make a post on Facebook or Craigslist and get a job in the mechanic business. That is a skill set I have and will work anywhere there are vehicles. I also already have the initial cost of tools covered as well.

I can charge $300-500 to do brakes on a car. I can do 4 brake jobs from 8 am to 5 pm.
That's $1200-2000 in a day.

Of course that's depending on clients. Most people are sketched out by indie mechs. Or want a hell of a discount.

I know I'll be able to get ahead with what I know. Situation depending.