This is the most cost affective I have found.
2 under bed trays $40., Rubbermaid container for res. $22., submersible pump $25., air pump and stone $12., 2 rockwool slabs $18., and a 2x4 table $6.
For about $150 a site you can set up a similar senerio. Under a 400 watter in a 3x4 are I was able to produce almost 500g. As you see here I now am running a perpetual system and am using 400's, 600's and 1000's. Totalling 5 sites like this. My grams per watt have increased to almost 1.5 grams per watt now.
This system has been very productive and easy to use. I am always looking for different ways but so far this has worked out really well
Hope this helps. PM me if you have any question.
Vaper