Several organizations post annual back-to-school shopping reports, which often include college-aged shoppers. Searching in Google for college students (shopping OR spending) retail survey and limited the results to the Past Year gets you many examples.
Pro tip: Pay careful attention to who publishes these reports. For example, the last one on this list excerpts many other reports, but the data selected is being used to promote a company that clearly has a stake in online shopping increasing. Can it be trusted to tell the whole story?
It's possible to tell two different stories from the same data. Here's a recent Washington Post Fact Check about how one candidate in Virginia's 2021 governor race is only "giving half the picture" when it comes to crime statistics.
Another place to look for what college students' purchasing habits or what persuades people to "shop small" might be academic studies. They might not all be specific to college students, but they could still provide useful data. These are the best JMU Libraries databases to search for that topic:
The best place to get information about student characteristics at any university is usually its office of Institutional Research and/or Effectiveness.
Economic development centers, non-profits or universities might have other reports or data that can be used.