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.

Economists worry that Trump's tariff plan will raise the prices of a range of imported goods, from cars to electronics.

President-elect Donald Trump threatened to impose sweeping new tariffs on Mexico, Canada and China as soon as he takes office as part of his effort to crack down on illegal immigration and drugs. He said he would impose a 25% tax on all products entering the country from Canada and Mexico,