Past ERP studies of economic transactions have shown effects on reward processing magnitude and valence (e.g., Yeung & Sanfey, 2004). To the best of our knowledge no study has directly investigated ERP correlates of buys versus non-buys. However, several ERP studies which have shown fluency effects guided our thinking. Paynter, Reder, and Kieffaber (2009) demonstrated that a frontal P200 and a fronto-central P300 index a “feeling of knowing” for arithmetic problems prior to retrieval, which they liken to perceptual fluency.