I was going to disagree with that on the basis that almost anything is on par, but then I thought of sourdough starter/levain, which is surely the easiest, chea

I was going to disagree with that on the basis that almost anything is on par, but then I thought of sourdough starter/levain, which is surely the easiest, cheapest, most versatile, most useful (almost everyone eats at least one kind of at least slightly leavened bread) home fermentation project. Once you get going it's very easy to always make your own bread, and it be lot better & cheaper (a sliding scale between them depending what you bought, but almost certainly both to some extent regardless) than what you bought before. Beer is trickier than hot sauce for sure, but more differentiable, versatile, and satisfying (if you drink beer) perhaps to make up for it on an RoI basis? Certainly worth trying if you like this sort of thing anyway, I think. Yoghurt is even easier than hot sauce, more versatile, though not really as interesting or variable. Such low investment though (milk, few chickpeas or chilli crowns) that if you use it at all it would be hard for it not to do very well on RoI basis.