Donald Trump's proposed tariffs on Canada could increase U.S. gas prices by up to 70 cents a gallon, energy experts say.

Put simply, tariffs are a tax on imports. Here's what Donald Trump did with them in his first term and how they impact the economy.

President-elect Donald Trump's threat to impose tariffs on Canada, China and Mexico on the first day of his administration could dramatically raise prices for Americans on everything from cars to clothes to oil.