Economic decision making is a complex process of integrating and comparing various aspects of economically relevant choice options. Neuroeconomics has made important progress in grounding these aspects of decision making in neural systems and the neurotransmitters therein. The dopaminergic and serotoninergic brain systems have been identified as key neurotransmitter systems involved in economic behavior. Both are known to be prone to significant changes during the adult lifespan. Similarly, economic behavior undergoes significant age-related changes over the course of the adult lifespan. Here we propose a triadic relationship between (a) economic decision making, (b) dopaminergic and serotonergic neuromodulation, and (c) aging. In this review, we describe the different relationships around this triad in detail and summarize current evidence that supports them. Based on the reviewed evidence, we propose new research agendas that take the entire triad into account.