Prior studies suggest that people are susceptible to the promotion framing effect. Yet it’s still unknown if income source moderates the effect of promotion frame on consumer decision-making and the underlying neural responses. The current study applied the event-related potentials (ERPs) approach to exploring the moderating role of income source (hard-earned income and windfall income) on the promotion framing effect in a cross-category bundling context. Two promotion frames were created with identical total prices for a cross-category bundle that included both hedonic and utilitarian products. The behavioral results showed that income source moderated the effect of promotion frame on neural responses and purchase decision-making. When participants obtained a hard-earned income, they showed an attenuated N2, an enlarged LPP amplitude, and a higher purchase rate in the hedonic (vs. utilitarian) freebie condition; but when they obtained a windfall income, the effect of promotion frame disappeared. Overall, the conclusions have important ramifications for both theory and practice.