Basically speaking the price of the related equipment you are inquiring about that is needed for a grow bucket system is quite expensive for what it does and what purpose it serves in the room it's an outdated technology and recent times have shown better system applications and designs using a "fertigation" automatic nutrient and acid injection feeding system(s). SDI subsurface drip irrigation is the technical trade term coined and used quite often to refer to this method. dosatron is a good example of a simple small scale unit, for novice applications.
Fertigation systems are potentially great, but I dont know of any that are workable for small scale, home growing. Plus, I seriously doubt anything like a 40% increase in yields. Its just a drip system you are talking about.
The smallest Dosatron for example has a minimum flow rate of .02 gallons per minute. Thats 28.8 gallons per day. Hardly practical for a small scale drain to waste system- - or even most large scale home setups. They are designed for continuous flow as far as I know, and dont work well scaled down to small flow rates.
Plus, they are not cheap, and you still need pumps, flow restrictors, pressure regulators, one way valves, timers, plumbing, filters, in-line PH meters, etc etc. AND you still need a rez full of concentrated nutes.
I dont see how its cheaper than a typical home bucket system or E/F setup using an aquarium pump and a cheap timer. Not even close to being in the same price range.