Comparing the cost of purchasing a bicycle with purchasing a motorized vehicle, bicycles are a far better alternative. Bicycles won't cost an arm and a leg to buy and they cost very little to maintain. They won't require gas and there will always be a cheap (often times free) parking space for them.
In a world made for convenience, there's little time or opportunity for exercise. People can easily dial the phone to have food delivered. They don't even have to get off the couch to change the TV channel. Bicycles offer a way to exercise while having fun. People shy away from just the thought of exercise but if it's coupled with an opportunity to see the sights, then it becomes more appealing. Most people would be able to ride a bicycle further than they can jog or run, and bicycling would broaden their world.
The world has also become filled with air pollution and noise pollution. The greenhouse effect has been thrown a lot when talking about vehicle emissions. The only negative output of riding a bicycle is the carbn dioxide exhaled while cycling. And people exhale even when not riding a bicycle so it's not so much caused by bicycles themselves.
There are so many advantages of using bicycles as transport. These advatages say that bicycles are cheap, healthy and clean.