This makes me wonder beyond salad dressing and granola:

What else is low effort to make and vastly better or cheaper than store-bought?

@jonobie sushi. No seriously, especially if you're vegetarian. The raw fish versions not so much (worth paying for safety there probably), but tamago, inari, kappa, and a whole world of whatever suits your fancy is dead simple to make and cheap.

Just get sushi-style rice, throw it in a rice cooker, then as it cools add sushi vinegar (possibly also sesame oil if you want). Once cooled & seasoned, put it on nori wrappers and then roll up whatever you like inside (or you can just stir-fry some stuff and mix it in and eat out of a bowl if you're lazy to do seaweed. One of my go-to lazy dinners skips even the stir-fry and just adds a bit of soy sauce and some store-bought crispy onions straight to the sushi rice.