My buddy is a badass artist too.
He worked in a shop just long enough to get his license or whatever it is they need to be "qualified", quit and opened his shop the same day.
He works out of his house. His setup is 100% legit though. Everything is sterile, top of the line equipment, etc.
I think his initial outlay was probably $2-$3k.
He's doing well over $500 a day right now, just a few hours a day, and the only reason I can get any work done from him without waiting for months is because I know him well. He's booked out forever.
He's been doing it maybe 6 months now on his own. His only source of leads is word of mouth. He gives anyone who refers 5 new customers to him a free tat, and he has to turn down business these days.
Definitely possible to bank as a freelance tattoo artist.
I live in a town of maybe 150k people, we have something like 50 tattoo shops in town, and he stays more than busy.
-Scott