DIY Plywood tank
So, here's my DIY Plywood tank. But for the actual plywood sheet which I had lying around I spent under 20 dollars, which, given the outside dimensions of 24x20x12 means I probably managed about $1 per gallon.
I used plywood, screws and glue, a stain (2 coats) , a polyurethane (3 coats), and a plastic liner with silicone to seal it together. I still have 2 more days of curing on the silicone then I get to see how it holds water.