Every day more than $4 billion worth of goods cross the United States’ borders with Canada and Mexico – U.S. auto parts headed for car factories in northern Mexico, cartons of Mexican avocados bound for California supermarkets, Canadian aluminum destined to become cans of Campbell Soup.

The 25% tax that President Donald Trump plans to slap as soon as Saturday on imports from Canada and Mexico could drive up the price of everything from gasoline to pickup trucks to the guacamole dip that features so prominently at American Super Bowl parties.