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 ...