Actually, best is a quantifiable quality, based on hard facts and statistics. You can break down "best" and see which food gives you the most nutritionally complete profile or the highest quality ingredients, or you can factor in price, which leads you to the greatest value. None of those qualities factor in cheapness though, and generally, that is never a criterion when discussing the best of a certain item. Cheapest things are usually far from the best, and with fish food especially, you're getting what you paid for. So, that said, I'm gonna have to politely disagree with everything you've contributed to the discussion so far.
which is better for my fish, good food or a filter? I don't have much $$$ to spare for better food, so the best i can do is get them somewhat cheaper foods that satisfy the fish.