Today I'm showing you the cheapest possible mob farm I could develop. It uses 0 Stress Units and can be built using any building block, andesite funnels, a windmill bearing, and sails. This farm produces 15,000 Mob drops per hour including 3,000 Gunpowder, 3,000 Arrows, 3,000 Bones, 3,000 Rotten Flesh, and 3,000 String. It also produces some spider eyes and drops from witches.