It's less about money and more about the mental energy required to distill such a granular view of money/value. $3 is basically the same as $10, or even $50. Even when I slept on the floor of an office building and made $10/hr I never thought like that. It is madness to me. Spend that energy thinking how to make $10 more, which is incredibly easy, far far easier than the mental energy micromanaging single dollars.