This chapter draws on Cicero’s letters to propose the existence of an “economy of goodwill” in the late Roman Republic. Through voluntas mutua, the mature statesman handles sensitive transactions and vouchsafes his allies’ support. I examine potential antecedents to Cicero’s goodwill in Aristotle’s theories of friendship (eunoia and philia), as well as in the system of “friendly loans” (mutuom argentum) in the comedies of Plautus. Cicero’s economics of friendship, though informed by these others, aim at problems particular to Rome’s fast-growing empire. Unlike normal currency, “spending” voluntas only increases one’s supply of it, allowing for mutual reinforcement of political support over time. Additionally, voluntas may be exchanged regardless of facultas, facilitating long-distance governance by low-cost trades of support across the empire when concrete beneficia are unfeasible. In his philosophical works, finally, Cicero shows an intriguing ambivalence about the economy of goodwill that served him so well in practice. Are reciprocal favors a defensible part of friendship? Though he excludes the possibility in De amicitia, in De officiis, voluntas mutua is redeemed in decorum, the ideal by which proportion and mutuality yield virtue.