Existing studies on comparative price advertisements mainly address how the physical factors of price presentation (e.g., font size, physical distance, background color) influence consumers' numerical processing and affect their discount perception and purchase intentions. However, this research takes a visual processing perspective to examine the visual balance effect of comparative price presentation (horizontal vs. vertical) on product preference. We used a scenario-based experimental design to imagine an online shopping scenario. Study 1 indicates that horizontal (vs. vertical) comparative prices lead to heightened product attitudes/purchase intentions. Study 2 verified that perceived stability mediates the visual balance effect. In addition, Study 3 shows that the visual balance effect is moderated by the fit of perceived stability with product characteristics. The conclusions contribute to the knowledge structure of comparative price presentation from a visual processing perspective and can guide more effective comparative price promotion.