The idiom that immediately comes to my mind is bang for your buck.
Bang for the buck is an idiom meaning the worth of one's money or exertion. The phrase originated from the slang usage of the words "bang" which means "excitement" and "buck" which means "money".1 Variations of the term include "bang for your buck," "bang for one's buck," "more bang for the buck," "bigger bang for the buck," and mixings of these. "More bang for the buck" was preceded by "more bounce to the ounce", an advertising slogan used in 1950 to market the carbonated soft drink Pepsi.
In your example sentence, you might say:
So next time you hold a dollar in your hand, remind yourself to get the most bang for your buck.