Earnings depend on the artist. Most are charging about $150 per hour now, however, they may not tattoo everyday! If you do two one hour tattoos in a week, you've only earned $300. Six one hour tattoos in a week, you've made $900....but, you have to pay taxes on all the money that you make and there is a lot of money that comes out of the fees that we charge. Rent, utilities, ink, needles, sterilization, incidentals such as paper towels, ink cups, cross contamination protection controls, etc...People never think about that when they are pricing a tattoo! It comes out to be about the same if you own the business or rent a booth. A renter gives up at least half or more of their fee and an owner has to cover ALL of the expenses of running a business. You can make a living being a tattoo artist, but you won't get rich, I promise!
Hours are maddening. Usually we work pretty late. People want to get tattooed outside of normal working hours! So that means we work the weird hours and never have dinner at the same time everyone else has dinner. It is not very conducive to relationships or raising kids!
As far as training, to start...you will need to be a decent artist. It takes about a year of technical training, but many, many years to become really good. There is no erasing! You get one shot to do it right!
You don't have to have "lots" of tattoos. However, I think that anyone inquiring about getting a tattoo would not be comfortable with an artist who didn't have any tattoos! There is no way that you can begin to know what your clients go through if you've never experienced it. They look at that seriously!
Whatever you do, never, never tattoo out of your house. You can not possibly begin to understand cross contamination and blood born pathogens without proper training. Also, the health department regulates tattooing and body piercing, they will not certify someone scratching out of their house and if you get caught, there can be serious repercussions. Legally as well as medically. You are putting people at serious risk every time you puncture the skin. If you don't know what you are doing it can land you in hot water!
Hope that helps. Good luck.