Hydroponics systems come in many varieties, each with it's own advantages and disadvantages.
Different plants require different systems as well.
For example, if one wanted to grow strawberries, one would use a nutrient film technique setup, due to the small root systems.
But if one wanted to grow tomatoes, they would want to use a system that allows much larger root growth room, such as deep water culture or ebb & flow.
In this article I will go over the basic system types to give you an idea of which system will fit you're needs.
Deep water culture systems are commonly referred to as the easiest and cheapest hydroponic setups.
Deep water culture systems are characterized by roots submerged directly in a water/nutrient reservoir, with air stones keeping the water oxygenated.
These systems don't often ofter the same growth rates as the more complicated setups, such as aeroponics.
If this is you're first hydroponic build, this is a very good choice.
Nutrient film technique systems are commonly used for smaller crops such as lettuce and strawberries.
They are more expensive than deep water culture setups because they require a water pump to circulate water from the reservoir through either PVC pipes or a similar growing container.
These systems offer good growth rates due to the high access to oxygen for the roots.
Aeroponics is regarded as the most complicated hydroponic setup, though also the system that provides the highest growth rates.
These systems work by misting the root systems, providing much more oxygen and nutrient absorption that any other system.
Aeroponics should only be attempted by someone who has built several hydroponic setups already.