Least expensive hydroponic garden in Florida

It depends on your creativity.....I have a large system on a timer and use a 55 gallon drum for solution. The most expense was the growing mix for me as I collected things for free to make it work. Towers, pump, tubing were all free...seeds came from dollar general at the end of the season sale...

what are you planning on growing?

Least expensive to set up (as a beginner) is the Kratky Method. No pumps or plumbing or electricity required. You just need tubs/containers, and some hydroponic nutrients, and off you go!