Depends very much on the community you live in. Where I live, just reading will supplement my income but won't make me financially independent, no matter how good I am. I'm also looking at getting courses I teach into the college system which will help a little (private classes, again, supplement my income but do not pay the bills), but even if I do get a series of courses accepted into the adult education system, I'd have to work about sixty hours a week to make a living (assessment and class preparation time is unpaid), and I wouldn't necessarily be offered enough classroom-time in any teaching venue to make it pay anyway - it's not always up to you how much you can do.
In a good venue with a good reputation, I can kick out up to about eight readings a day a couple of days a week - at the moment my exposure is less than that. Considering that my rent for my home alone is worth about sixteen or seventeen readings, it's not a path to instant riches.
If anyone is hanging around here believing that Tarot will one day make you rich, you're looking in the wrong place, even if a single reading you may have had seems expensive. After all, it probably took that person twenty years of study to achieve their level of skill, all of which has to be divided into the price of the reading, in most places they will have overheads (rent or a percentage for the house), transport, wear and tear on decks, cloths, candles, incense etc, even lunch.
This is something you really need to do because you love it, or you will face disappointment and disillusion full in the face.