What is the easiest /cheapest hydroponics system that a student can make from almost everyday items

Its not that simple to explain how to make a cheap hydroponic system and there are several diys and tutorials available online for it but simply put it should have an air pump, a nutrient reservoir from which air is passed through a pump to move the nutrient. floating plant containers on a water surface in which the nutrient is added at the bottom and an exit for nutrient to be recycled out..

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