The economics of who actually bears a tariff, what economists call its incidence, is more nuanced than either "foreigners pay it" or "consumers pay all of it." The legal payer is the importer. From there, how much of the cost is passed through to buyers depends on how sensitive demand is to price and on how much competition there is. For a good with few substitutes, more of the tariff tends to reach the consumer; where buyers can readily switch to untaxed alternatives, importers and retailers may absorb more of it to keep sales, or buyers shift their purchases. Some of the burden can also fall on the foreign producer if it cuts its price to stay competitive. The realistic answer is that the cost is shared, and studies of specific tariff episodes have generally found that a substantial share reaches domestic buyers.
Tariffs serve several policy purposes at once, which is why they are contentious. They raise revenue for the government. They protect domestic producers by making imported competitors more expensive, which can preserve domestic jobs in the protected industry, at the cost of higher prices for everyone who buys the product and for domestic manufacturers who use the imported item as an input. And they function as leverage in trade negotiations, sometimes prompting other countries to impose retaliatory tariffs on exports, which can hurt domestic industries that sell abroad, agriculture prominent among them. The net effect on the broader economy is debated among economists, but the direct effect on the price of the taxed goods is not: it is upward.
For personal finance, three channels are worth tracking. First, prices: tariffs on consumer goods, or on components and materials that go into them, tend to raise the prices households pay, contributing to inflation in the affected categories. Second, investments: companies that rely on imported inputs or that export into markets that retaliate can see profit margins squeezed, which can weigh on their stock prices, while some domestic producers shielded from foreign competition may benefit, so the portfolio effect is uneven and industry-specific. Third, behavior: because tariff policy can shift quickly and unpredictably, it is a source of the kind of headline risk that a long-term investor is generally better off riding through than trading around. The sensible posture is to understand which of one's spending and holdings are exposed, not to forecast the next policy move.