There are many types of exercise bikes. There are the very cheap ones that don't work, but do nothing for you at all.
You can buy a cheap and low quality BMX bike that works okay for you but is overpriced for what it offers. These bikes only provide basic motion to the user, which gives you a limited amount of moving motion, and isn't great for you in the long run.
Exercise bikes for the do-it-yourselfer are perfect for the serious fitness enthusiast. For the price, they don't cost much. They give you a solid base to build on with exercise.
Many of them are geared towards a specific area like building muscle, burning fat, getting in shape, etc. Others are designed to increase your range of motion. The ones that do not help with anything are usually cheap and forgettable.
Types of exercise bikes include road bikes, cross trainers, recumbent bikes, stationary bikes, power walkers, and so forth. Each one has its own use and feature set.
Activity bikes are primarily intended for endurance training. They are mostly designed for everyday use by athletes or those who wish to stay in shape but don't want to spend a lot of money on exercise equipment.
For all the people who enjoy walking but need a bit more to keep their hearts racing. These types of bikes allow you to pedal like a normal person would, with only the motion that moves you.
They are similar to the gym machines but they aren't made to be perfect. These bikes have a small engine and are generally noisy as well. If you're looking for something less expensive but still provides a little workout, a single speed trainer is an option. The only problem with this type of exercise bike is the fact that you need to pedal very slowly to get the maximum effect.
Cardio bikes can also be classified as they improve the performance of your cardio by providing greater resistance to the legs. They are designed to be used with a trainer while adding some type of resistance to help with cardiovascular exercises.
Cross trainers are meant to target the lower body muscles. They are great if you need an easier and lower-cost alternative to the heavy and hard machines.
They may not be a complete program to get you in the best shape of your life, but they will help you get some workouts in. This is an option if you want to learn how to exercise but don't want to break the bank doing it.