An aquarium water pump https://www.ntotank.com/20gallon-duracast-rv-water-tank-x348..., a liquid holding container https://www.ntotank.com/20gallon-duracast-rv-water-tank-x348..., one or more large Tupperware (or whatever you find) tray(s) draining back into the liquid holder, Rockwell bricks (or another grow medium) in the trays, a cheap timer for the pump and you have your own ebb and flow system for a couple hundred bucks.

I've build several of these over the years. There's no need to spend extra money. But the soil and the sun are free if you can get it and imo better.