By day, Mr. Page teaches personal finance and economics to high school students, and as the stores disappeared from his rearview mirror he had an idea. “I wanted my students to feel how dirty it is,” he said. “You can talk about these places and show them the math on the fees, but I wanted them to feel it.”Some of them already know what it means to struggle. Mr. Page teaches at Reading High School, which is pretty representative of America, with students who have occasionally ended up in jail or had children of their own or reckon with relatives who have stolen their identities. Still, they’re at the beginning of their financial lives, and he’s constantly looking for ever more visceral ways to reinforce the importance of good savings habits, great credit scores and low fees.