In practice, many prominent electronic retailers (e‐tailers) offer consumers both self‐run (i.e., reselling mode) and third‐party (i.e., agency selling mode) sales channels. However, previous research has not explained how consumers choose between these two channels and the potential moderating factors of that choice. To narrow this gap in the literature, we conducted a cognitive neuroscience‐based experiment and a scenario‐based experiment to investigate how the consumers' purchase intention is impacted by e‐commerce sales channels (self‐run vs. third‐party) and review volume (low vs. high). As per the results of the experiments, the participants were more likely to buy from the self‐run (vs. third‐party) channel when the review volume was low; however, they did not differ in their purchase intention between the self‐run and third‐party channels when the review volume was high (Studies 1 and 2). The neuroscience data yielded similar findings: When the review volume was low, the self‐run channel elicited more pronounced electroencephalography activity regarding the late positive potential (LPP) than the third‐party channel; when the review volume was high, there was no difference in the LPP induced by the two sales channels (Study 1). In addition, the interaction effect between sales channel and review volume on purchase intention was mediated by perceived product quality (Study 2). Based on these findings, we discussed the theoretical and practical implications of the research.