This study analyzed the impact of the sugar-sweetened beverage tax (SBT) on consumer purchasing behaviors by using Nielsen consumer panel data from Cook County, Illinois, from 2017 to 2018. Our research focused on the responses of different consumer groups—including SNAP recipients and general consumers—to various beverage types, such as sugar-sweetened beverages (SSB) and artificially sweetened beverages (ASB). We employed Cook County as the treatment group and the other counties in Illinois as the control group. Results indicate that during the implementation of the SBT policy, total beverage volume sales in Cook County significantly decreased. However, the effect of the policy on reducing consumption diminished and disappeared by the second month after the policy was repealed. Furthermore, regular consumers reduced their consumption of taxed beverages following the policy, while SNAP users showed a limited response to the sugar tax. The limited response among SNAP users can be attributed to their strong cravings for unhealthy foods, cognitive reduction caused by the tunneling effect of scarcity, and dependence on high-sugar foods. This research reveals the differentiated impact of SBT across socio-economic backgrounds and provides empirical evidence for formulating public health policies.