Capitum

Local soda distributors like coca cola or pepsi plants. It has been a few years, but last time I went to one they gave me about 4 55g plastic barrels, and about 20 5-gal pails. Free. I've also found more recently that the local grocery store's bakery will sell 5-gal pails for $1, which is even cheaper than the local big-box store (no, my nanners aren't that big, I'm just contributing relevant info)

I went on a tour of a local greenhouse who does intensive fruit farming in bags; each bag was in the 2-gal range and were on drip irrigation multiple times per day, with some very specific micronutrients added based on what was growing. He had fruit trees producing several years faster than in the ground, would grow them for 3-5 years, then discard the trees as they got too big and were past their production prime. He sold fruit to the local school system, it was a good sized operation. It had the extra advantage of mobility, although I suspect he didn't move trees around often. He also had them packed really close together. I had thought about that for bananas, but I don't have a greenhouse yet and definitely don't have the micronutrient knowledge or the automated systems needed to keep stuff alive in an environment with such low tolerance for screw-ups. Just curious, what is the smallest container (hydroponics or otherwise) that anyone has gotten fruit in?