Article originally found in sc4ever.com
Toll booths are quite possibly the most unbalanced thing in SC4K. For a modest fee, you can get 20 cents per month for every car or bus passenger that travels through the toll. This can be abused to make massive amounts of money. I've had a city that made $10 000 profit per month on tolls alone.
Toll booths are pretty simple. Your Sims usually travel from residential to industrial, or residential to commercial. If their route goes through a toll booth, they give you $.10/month. Toll booths add a few minutes to their trip, and give you money in the process.
Build a ground highway to connect your residential and industrial zones. Make sure it's the only road connecting them. Place avenues at the ends of the highways, and connect them. Now, put toll booths all along the ground highway. Do the same thing between residential and commercial zones.
Now wait a few months, and check your income. You should be making huge amounts of income from the tolls! As long as the sims have to take that highway to work, they'll pay a huge amount in tolls. A well set up network will give you more money from tolls, than you will get from residential taxes. (Sick, no?)
Even Sims that take the bus have to pay the toll. But, busses don't make congestion like cars do, so they can drive around the toll more easily than cars. Make sure they can't, so you can get income from bus fares, and the toll.
If the highway gets cramped, build another one, set up the tolls, and connect it to the same avenue. Build bus stations to reduce congestion, and make more money at the same time.
Why ground highways? Ground highways are cheap. Highway toll booths handle the most amount of sims. Sims drive the fastest on highways, so more sims will be able to get to work. A good highway can have 8 tolls, giving you $1.60/month for every car or bus passenger that needs to travel on that highway. Sims pay 10 cents on the way to work, and 10 cents on the way back.
Toll booths cost $5 a month to maintain. So, as long as you get 50 cars going through, you'll break even.
One last word of caution: Toll booths add up to your commute time quickly. If your sims have a commute time more than 100 minutes, they'll start to lose their jobs, and leave your town. You'll still get bucketloads of cash, but a few buildings will rot. It's nothing to worry about on a small or medium map, but be careful in region play.