Mere talk of tariffs will spur some consumers to run out and buy big-ticket items, or stockpile smaller ones, on the theory that prices will soon rise. That behavior, alone, could make prices increase . If Trump announces tariffs on his first day in office, as he has suggested, some prices could spike immediately.

Mexico said Wednesday the United States will be shooting itself in the foot if President-elect Donald Trump implements his threats to impose 25-percent tariffs on Mexican imports.He said he would charge 25 percent tariffs on Mexican and Canadian imports and 10 percent on Chinese goods "above any additional tariffs" on the world's second-biggest economy.

Trump, who takes office on Jan. 20, said he would impose a 25% tariff on imports from Canada and Mexico until they clamped down on drugs, particularly fentanyl, and migrants crossing the border, in a move that would appear to violate a free-trade deal.