I worked as a taxi driver for six months in a small (~70k) city. Here's how it worked.
Shifts were twelve hours, and there were no on street pick-ups. You had to be dispatched from the central company. You began your shift by renting a cab ($50 a day -- all money in 2006 dollars). Hopefully it would be running okay, because after twelve hours in a cab with bad shocks, you'd feel beaten up. You paid twenty-five cents for each mile you drove to the cab company at the end of each shift. This usually worked out to be about $25-$30, so a regular twelve hour shift would be about 100 to 120 miles.
A fare anywhere in town was six dollars. Didn't matter if it was a two minute ride or a half an hour ride: $6. Of that, the cab company got three dollars. However, if they had a token, which were sold at all of the local grocery stores and employment agencies, you had to take that. A token cost the riders three dollars, of which the cab company would pay you out $1.50. Ninety percent or more of fares, in my experience, used tokens to pay for rides. The town had no serious public transit system, so people who used cabs tended to use them regularly, and planned ahead.
Tipping was very much optional, and almost always non-existent. At the end of the day, you had to wash the cab, and you'd have to fill it up with gas. These were big ol' decommissioned Crown Vic police cars, and they got maybe 20mpg, if you were lucky. Depending on the car, it could be a lot worse.
There were a couple of factors at work on how much money you were making. The main one was if the dispatcher liked you. The most lucrative fares were out to the airport, a forty minute drive away. You might be gone for an hour and a half, but it was $60. In the six months I drove a cab, I got one of these. The dispatcher would assign you your fare and you'd have to go get them.
Days were usually easier, because people weren't drunk, but they also paid less. It was mostly people who were going to work but had lost their licenses for DUI, or the severely mentally handicapped going to adult day care or work programs who weren't able to drive in the first place. These people always used tokens, and they often lived in out of the way places and would travel halfway across the county to get where they were going.
Nights were harder, but you made slightly more money. Drunks were trouble. Some could be threatening, one threw up in my cab and I had to wash the car twice in one day. Several jumped out of the cab and went tearing off without paying. That caused its own problems. The first time, I had the dispatcher call the cops, and they came and knocked on the door and no one answered, and the cops shrugged and drove off. Took about forty minutes. Afterwards, I just decided it wasn't worth the last time. I could have picked up and delivered a fare in the time I sat and waited for the cops to go through the motions.
Most days I walked away with maybe twenty or thirty dollars, after cashing out and filling the car. I once made $100 (airport trip) -- that was the most I made. One day -- my last day -- I lost money. It's probably easier in a bigger city, but I can't imagine it's all that great.
So, when people complain about how badly Uber treats their drivers, it really makes me wonder. I use Uber because the city I live in now (~250k) is next to a much bigger city, and has extensive public transit, including light and commuter rail and buses. But the buses don't run after midnight, and the train doesn't go to my apartment. So I take cabs. And I can't tell you how many times, prior to Uber, I would call for a cab to go to the airport and they just wouldn't show. You had to build an extra hour into getting to the airport just to account for the cab. It's a bad system.