This cartoon IS set in New York right? I work at a clothing store so I get the reverse of this every day, the rule is that there is no sales tax on clothing provided the garment costs less than $110, but certain accessories such as purses and bags DO charge sales tax. Groceries are also something that doesn't charge tax unless it's candy. You can buy all the bread, meat, and veggies you want and not pay a dime in tax, but you're gonna fork over that 8.875% for a candy bar.
Also this cartoon was made years before "Pizza Gate" but I would LOVE it if it turned out this candy store didn't even have a basement.